[quote=@Mammalia]
<Snipped quote by Host>

Why are they called that? Are they just really long?
[/quote]

Naruto has like 500 episodes and like 350 are filler. Read the manga if you go into naruto.
One piece is overrated but good, though it drags out a ton and gets boring for a while every so often before something new is introduced.
Bleach is good but suffers from filler and ends early, so read the manga for it too.

Or go back a page and go off that list. :/