Continuity mistake: Jerry was forced to take the phone call thanks to Kramer. He is holding the receiver in a different way between shots - look at the position of the index, on the microphone in the second shot. (00:03:50)
Continuity mistake: Elaine joins the other late at the table. She sighs and puts her sunglasses on the table, above an open menu. Brief cut to George, and the menu is on top of The Glasses. It is again at the bottom later. (00:01:45)
Continuity mistake: During the initial conversation, George keeps playing with the paper sleeve of a straw in certain shots, while his hand is in another position in the reverse shots (noticeable for instance when he says "Guys with cats...I don't know..." (00:02:30)
Continuity mistake: Jerry says that he wants to suggest to his current girlfriend, Vanessa, to go away for a couple days. George starts saying "No no no" and before the cut he raises his arm and lowers his head as to express concern. But in the new shot there's no trace of that change in posture. (00:02:45)
Continuity mistake: When Elaine passes the newspaper to George, Jerry is sitting normally in the first shot, leaning with his right arm on the backseat in the next. (00:03:10)
Continuity mistake: Jerry orders a tuna sandwich, and Elaine turns towards him and whines "Tuna?" Her hand is still on the menu, but when the angle changes her hand is on the neckline of her top. (00:04:50)
Continuity mistake: The scene with Elaine on The Couch plotting the demise of the cats begins with a nasal spray on the kitchen counter. There's no trace of it after that initial shot, and it reappears only when Elaine comes closer for her cup of coffee. (00:13:00)
Continuity mistake: Kramer runs off to meet the girl he just spotted through the binoculars, and George walks through the door and crashes on The Couch. The pillow is straight-ish, very angled and straight again during the conversation, with George's hand changing position between shots. (00:15:45)
Continuity mistake: Elaine comes out of the bathroom sniffling and with a big stripe of toilet paper. She rubs her left side of the nose when she asks "Didn't work, huh?" In the next shot with George answering with a burst of nervous laughter, Elaine's hand is in a different position, and George himself is clutching a tissue to his chest. (00:16:25)
Continuity mistake: Up in Vermont, Jerry is beginning to have a rather tense conversation with Vanessa. In the close-up after the watch comment (when he is thinking of the delightful drive home ahead) Seinfeld is all smiles, but in the shot before and after he is staring with a tense expression. (00:17:20)
Continuity mistake: When Elaine joins Jerry and George at The Cafe and tells them she spent ten minutes looking for a grape, keep an eye on the straw in George's drink. From shot to shot, the straw in George's drink keeps changing position, from tilted to upright, then tilted at The Opposite end of the glass, then upright again, then back to tilted.
Continuity mistake: In the very first shot of Jerry's conversation with George's ex, behind the pile of books you can spot a big lemon slice on the rim of the glass. The slice is then gone from that spot (it's inside the glass now, submerged by the drink), but between shots it is back on and then off again. (00:08:00)
Continuity mistake: Kramer and Jerry are talking about Marlene. Kramer says "Why would George want to deprive you of pleasure? Is it just me?"; he raised both hands chest-high. At the cut, his right hand is lowered. (00:16:00)
Continuity mistake: Kramer leaves with the cantaloupe saying "Well, I am taking this back"; not only he grabbed the fruit during a cut at breakneck speed, but the towel on the station changed also position. (00:17:00)
Continuity mistake: The first time we see Jerry's dad, he's passively taking his wife's whine about The Jacket, remote control on his chest and hands crossed on his belly. Cut, and he is sitting with his arm by his sides. (00:01:00)
Continuity mistake: At the family dinner, Jerry's mom mentions horses for the first time. Reaction shot on the old lady saying "yeah, yeah", and cut to a wider angle; she is now all of a sudden leaning on her right arm. (00:06:50)
Continuity mistake: Jerry and Kramer are arguing about the bet when Kramer is having a glass of milk. The phone rings cutting them off, and Kramer's glass suddenly from his mouth goes to his hip. (00:10:25)
Continuity mistake: Jerry called his parents back to tell them about Myra's dead. When his dad at the end of the scene says "You know what this funeral's gonna wind up costing me?" Barney Martin is leaning his head against his hand all of a sudden. (00:12:50)
Continuity mistake: Jerry and his friends are eating, and Elaine opens defending The Pony Remark saying she was just having conversation. She gestures with both hands free, but then at the cut she asks Jerry about the game holding a teaspoon. (00:13:35)
Continuity mistake: During their casual talk about death and wasting your own life, George says he plans to continue wasting it. Cut, and both him and Elaine are in different poses than earlier, with Elaine licking the spoon and George with his fingertips by his mouth. In the majority of the conversation there are no such jumpcuts and continuity is kept. (00:14:45)
Answer: Composer Jonathan Wolff used a synthesizer, although in seasons 7-9, a real bass is used in addition. Wolff also recorded himself making hundreds of mouth noises, pops, and slaps to add to the synthesized bass licks so that each episode has a different theme. The only real "back-story" is Jerry Seinfeld was having trouble coming up with a theme song and talked to a friend who happened to know Wolff. They wanted to avoid that cheesy late 80's sit-com theme song and Wolff came up with what we enjoy now. Jonathan Wolff has also talked about this further in interviews, recently Reed Dunela interviewed him, so for a fuller account of his story; check out "The Wolff of 116th street".
Bishop73