I've been going to 4chan for all my needs for the past five, maybe six years. Maybe even longer. It gives me a laugh, makes me think, grosses me out, and has some good fap material.
Some of the best threads can be found on /b/, but they are far too often buried underneath a pile of shit 10 pages deep. Either that, or it's gone in 13 seconds because some asshole made ANOTHER You Laugh You Lose thread.
I do have to say, though, the whole thread filled with Men Laughing At Fruit Salad killed me. Another worth noting are the Rate My Band threads. I laugh so hard I cry every time I stumble upon one.
Altogether though? 4chan is a nice thing to do every so often. Like twice a month or something. Don't go on more than three times a week. After that, it's a little ridiculous. You start knowing things you shouldn't. Like porn star names, what goatsee is, what an anus looks like after rough anal sex, what it looks like when a woman sucks off a horse, how to make mustard gas, what a diseased vigina looks like, and how to make some of the best biscuits ever.