Lorean Stinchcomb
Lorean Stinchcomb voted up Echo Jones' answer

Flanderization ... A single trait, until that trait takes over your whole character. That kind of sounds like peer pressure to me .

Lorean Stinchcomb
Lorean Stinchcomb voted up Levi Fitzsimmons' answer

It happens a lot in comedies because writers think the character is only funny when that trait is present. So they emphasize it more, then it becomes exaggerated, then it completely consumes the character, often to the point that it ruins the character and ceases to be funny.