Continuity mistake: Several times during the tsunamis, in the week of 8/1/05, Sam Bennett's shirt would switch between being yellow to a light orange from shot to shot. The orange shirt was distinctly darker than the yellow one, even when both were soaking wet. Actor James Hyde was wearing the yellow shirt, but his stunt double had the orange one.
Continuity mistake: When the show started in July of 1999, Gwen Hotchkiss and Sheridan Crane barely knew each other. When Gwen and Ethan were on the beach in Harmony, Gwen asked Ethan many questions about Sheridan. Later, when Gwen and Sheridan met in Paris, Sheridan asked Gwen a lot about her relationship with Ethan. Both exchanges made it clear that Gwen and Sheridan were not well acquainted. However, years later, Gwen and Sheridan often spoke about having been lifelong friends, even though they had only known each other for a few years.
Plot hole: A person can typically survive for only about five minutes without oxygen. It's not entirely clear how much time elapsed after Beth and Charlie dumped Sheridan into the water on 9/25/03, but we do know that before she resurfaced, the women returned to the dock, Luis took the same boat back out onto the water, and then returned to the dock as well and made it all the way to Beth's house. This must have taken much longer than five minutes. Yet, inexplicably, Sheridan - who had given birth to a baby just hours earlier - was still alive when she was brought to the hospital on 10/8/03.
Continuity mistake: Throughout 2000-2001, the character of Ethan Crane was said to have three sisters who were all away at boarding school. By 2003, he instead had just two still-absent sisters, and a brother, Fox, who now appears on the show. (By siblings, I mean children who were raised as Julian and Ivy's.)
Continuity mistake: On 2/1/05, at the beginning of the episode, Gwen cornered Theresa and tried to stab her with scissors. Theresa was in her wheelchair, backed up against a wall, and Gwen was standing right over her. Gwen swung her arm, and a wet thud was heard. Then it went to the credits. When it came back, there was a medical supply cart between them, and Theresa was using it to fend Gwen off. But the cart hadn't been seen before, and would have needed to already be between Gwen and Theresa in the last wide shot in order for Theresa to use it like she did just a few seconds later.
Character mistake: On 3/10/06, Endora sneezed and Tabitha said "Bless you." Since Tabitha is a witch, and holy water and crosses burn her skin, and she can't enter a church, and any time Edna used to mention angels it caused Tabitha's entire house to shake, it should definitely be impossible for Tabitha to say "Bless you." The little girl sneezing was probably unscripted, and "Bless you" was the natural response of actress Juliet Mills.
Continuity mistake: On 7/19/06, Tabitha told Endora that Siren's aphrodesiac stew was more powerful than her own lust potion. On 7/21/06, Tabitha told Siren that the lust potion was ten times as powerful as the stew.
Continuity mistake: On 9/15/05, Ethan referred to Grace Nancier's plea offer as three fifteen year sentences, "served concurrently." But the offer was for sentences served consecutively, which is a big difference.
Factual error: On 7/29/05, the men at the Tsunami Warning Center talked about the tsunami that was heading towards Harmony, and then the scene shifted to a giant wave. However, the shot was of a large, cresting ocean surface wave. Tsunamis are very different from surface waves in many ways, the most notable of which is that a tsunami at sea is only a few feet tall at most. Even when it approaches land it behaves like a violently oncoming tide, not a cresting wave.
Continuity mistake: Throughout December, it was explicitly stated over and over again that Sheridan and Luis were getting married on the day after Christmas. But on 12/31/04, their wedding was still going on, yet it was New Year's Eve.
Plot hole: When Sheridan wakes up in the hospital on 12/16/03, she doesn't remember what has happened to her. But she was fully awake when she fell off the cliff, and despite being shaken after she was pulled to safety, she walked off with Antonio and Luis so they could take her to the hospital. There is no point at which she lost consciousness, and there's no reason for her to be so confused.
Continuity mistake: On 6/24/05, Sam and Luis were trying to break through a wall in the Crane mansion. The sound of metal on metal is heard, and Pilar asks what has happened. Luis and Sam explain that they've just hit a metal barrier that they think must conceal the room they're looking for. But several square feet of metal are already exposed. Why wasn't the metallic sound heard earlier, and why is everyone acting like they've only just discovered this second barrier?
Continuity mistake: On 10/19/04, Fox refers to Ethan as his "oldest half-brother," but in reality Chad is his oldest half-brother. Fox is specifically thinking about all the changes to his family, and everyone knows that Julian was with Eve before he married Ivy, so it's a no-brainer that Chad is older than Ethan.
Plot hole: On 8/10/04, Luis asks everyone where Paloma got the necklace with the Crane Industries logo on it. Katherine tells him that a man gave it to her, "a few weeks ago." Although the episode in which those events happened did indeed air several weeks earlier, it was the morning of the same day as experienced by the characters.
Continuity mistake: Throughout December, 2004, Luis and Sheridan talked about how their wedding would be the day after Christmas. Then, during the several episodes that took place on Christmas Eve, there was a Christmas tree lighting and the characters went to midnight mass. After that, Luis and Sheirdan went to bed together on 12/27/04 and woke up together on 12/28/04, and it was their wedding day, when it should instead have been Christmas Day, the day before their wedding.
Revealing mistake: On 12/24/03 and 12/25/03, Sheridan is supposed to be breastfeeding baby Martin. But Sheridan's shirt is barely unbuttoned, and pulled aside only marginally (and mostly from the opposite side of where the baby is). For his part, the baby is not even turned towards Sheridan's body. So, the way the scenes are shot, there's no way he could be nursing.
Continuity mistake: On 9/27/99, in LA, Henry gives Chad a newspaper that was left in his family's apartment when Chad was abandoned at age eight. It is a Harmony Herald. Then we see Theresa and Whitney walking in front of a Harmony Herald newspaper box in Harmony, and the paper is identical to the one that Chad's family left behind about a decade earlier.
Plot hole: On 1/3/06, after the smoky downdraft drove everyone from the living room, characters became separated from each other and spent several scenes trying to find one another. Shortly after everyone reunited into small groups, they received text messages on their cell phones, causing them to return to the living room. But if all these people had their cell phones on them, why didn't anybody try calling their loved ones instead of wandering around aimlessly?
Continuity mistake: On 7/19/05, Luis mentions his and Sheridan's past life in ancient Egypt. The viewers know about this past life, because Tabitha told Timmy about it. However, unlike their past lives on the Titanic and in 19th century America, which they experienced firsthand, Luis and Sheridan themselves never learned about their past life as Antony and Cleopatra.
Plot hole: Martin and Katherine have been living under the assumed names of Bob and Ellen Wheeler. Despite forming very close bonds with several characters prior to falling out of favor with the revelation of Martin's real identity, they were almost never referred to as "Bob and Ellen." Almost everybody called them "Mr. and Mrs. Wheeler" at all times, even though the entire rest of the town is on a first name basis, even with the wealthy and powerful Alistair Crane. Martin and Katherine themselves called everyone else by their first names, and such forms of address are almost always reciprocal among adults.
Answer: I don't know about good not wanting them to be together, but I know the evil side doesn't want them together because once they sleep together, then Charity's powers will multiply, and she will be a driving force against the evil darkside.