Why do you think the San Diego Chargers always choke in the playoffs, post-season in a weak AFC West Division?

C'mon, the San Diego Chargers have pretty much not competed with anybody in the AFC west for the past few years, the Chiefs, Broncos, and especially Raiders have been weak, so it's like, why are the Chargers unable to reach the Super Bowl? Why do they do so good in the regular season but come up short in the post-season? Do the Chargers just love coming up with new ways to dissapoint their fans?