I realize this is a massive, massive over generalization but I gotta be honest: most warriors I've met haven't necessarily been...well, intelligent.
Some examples recently:
-Pre-BC, me and my guild were in AQ40 when one of the other rogues in our guild said "I just drank a mongoose potion, so I'll invariably die on this pull." One of our main tanks in the guild asked "what's that word mean?". Shocked by the stupidity of the question, I just quickly responded with "not a variable". Most of us believed that would be the end of it, then the warrior asked "What's a variable?" The warrior is a freshman in college.
-One time (post-BC) I was the leader in a Ramparts run. Having never been in the ramparts before though, I didn't know what target priorities were. I kindly asked in the party chat this simple question, when I got a /w from our warrior (not the same one) asking what a priority was.
-One time (post BC) when debating damage formulas with another rogue over Ventrilo, another completely different warrior logs on to the server. He hears me saying "the damage is basically your attack power squared times .3". He then asks over ventrilo "omg since when did rogues get an AoE?". I, thinking he was talking about blade flurry, said we've always had it. He quickly corrects me and goes "no, the thing about how you said eviscerate does square damage".
-In HP, I was attacked by a level 70 warrior while I was killing a mob. I finished off the mob and, looking for an escape, realized that I was on top of a pretty big hill. I blinded said warrior, and jumped off said hill. I survived the fall, taking about 2000 damage and restealthed. I figured that would be the end of it, but lo and behold here comes Mr. 70 warrior jumping off the cliff as well. The fall nearly kills him (he's flashing red) and then to top things off, he SITS DOWN AND BEGINS EATING. I ambushed him, taking advantage of the 100% crit chance and basically got a free HK.
I hate to see warriors fit this stereotype, but sadly a LOT of them do. I guess getting beaten senseless by mobs doesn't do their brains very well.

