I swear im the only one on these forums who likes Naruto
I like it, loved it for years (manga though-anime has too much filler). There are so many great animes out there to watch if you want to kill time. Does come down to your taste though.
You know you could always take up a sport if your that bored, like start jogging it can be quite relaxing for some. I personally like to take late night walks and listen to sad music, helps me think.
One word:
Fillers. 
I don't know about others, but I like animes that are, let's say, 50 episodes or under. When it goes beyond that, it just becomes a soap opera. When I was a kid I used to watch DBZ, Pokemon, Digimon, and all the usual stuff that came on Toonami, but I was younger and more accepting. Now I prefer the short and sweet stuff. Though at the end of some of them I wish they had a hundred more episodes, but it's probably better they don't.
Oh the filler! The filler!

Wouldn't bother me if they actually thought of good arcs to write.
I'm usually not a fan of long running anime series, too much effort. Some of my favorite series are 12 or 25 episodes and only have 1 season. I love watching those series I know i'll never forget. Eden of the East for example, love it!