Continuity mistake: When Kenan and Kel are in Kenan's room there are 2 socks hanging out of the dresser the one on the left keeps changing positions.
The Cold War - S1-E8
Continuity mistake: Kel drinks a fair bit of Kenan's "medicine" but in the next shot the amount of "medicine" is greater than before.
Continuity mistake: Kel comes into Rigby's and sits on the counter and takes of one of his trainers, after he has been handing out fliers. He puts it on the counter so the sole of it faces the camera all the time, yet during shots it suddenly changes so that the top of the trainer faces the camera.
Continuity mistake: Just before and when the president it in Rigby's The clock keeps changing time.
Merry Christmas, Kenan - S1-E11
Continuity mistake: When Kel knocks the Christmas tree over the star lands by Roger's feet but appears on Roger's head as he stands up.
Doing Things The Hemingway - S1-E3
Continuity mistake: Kel is attempting a life goal and attempts to put 50 grapes in his mouth. When he spits them out there is about 10, nowhere near what Kel then claims is 33 grapes.
Continuity mistake: When the President is in the shop and the tower of Orange Soda is about to collapse, watch Kenan. He puts his arm through the display to make it collapse.
The Cold War - S1-E8
Continuity mistake: The clock in Rigby's is changing time throughout. (00:04:00)
Continuity mistake: In the episode when the president comes into Rigby's, near the start Kenan fixes the slush-o machine, but it doesn't work, and slush-o sprays all over Chris. Afterwards, one of the slush cups on the counter falls over. After that, the cup keeps on vanishing then reappearing.
Doing Things The Hemingway - S1-E3
Continuity mistake: When Kel jumps into the window cleaners' bench it's only a fraction down from the roof. no more than 6ft. Next shot with Kenan the bench is further down.
Continuity mistake: When the President is being crushed in the Oval Office, Kel opens the sliding door. The door stays open but when left alone Kenan and Kel go to look at it and it is now closed.
Continuity mistake: There is a 5 minute scene in Rigby's at the end but the clock doesn't move at all.
Continuity mistake: Mo Sweater Blues: For the amount of water Kel splashes on Kenan the wet patch is way to big.
Answer: He's simply enjoying doing it himself. Especially since he likely believes he can do it better than she can.