Never understood the popularity of this show. Taket the first youtube clip as an example. The guy keeps saying he needs wood and the other two laugh because it is so funny that the first guy doesn't know that "wood" means having an erection. Apparently this is hilarious and is the premise of this portion of the show. I guess if I was in junior high I might get a kick out of it, but seriously? This is considered funny? If this passes for cutting edge comedy than I guess I'll just have to live on in ignorance and rely on re-runs of Frasier, Sienfeld, and the early years of The Office.
Out of context, that particular gag would indeed elicit a "huh? That's funny?!?!" response.
But IN context of what the one character is all about, it's at least mildly funny. Don't pass judgment based on that one clip, as it doesn't really give you much idea of the show. You really ought to view a full episode or two, preferably the early ones, when the main characters still didn't know each other that well.
Personally I found Fraiser and Seinfeld to be more stale after a few years, while Big Bang is still <usually> fresh. I had been thinking The Office was starting to lose it's way last year, but lately with a slight change in tone and the regular appearance of James Spader somehow works well again.