Characters that are stuck in the past?
An example of this is the character Gary king from the movie "The Worlds End". Gary was super popular in high school , had his best friends, decent grades, Pretty good life, decades later, we find out he failed to succeed in life, all his friends have jobs and families, except him, and he can't stop trying to replicate his teenage years, it's all he thinks about. Pretty much a great example of a "peaked in high school" character.