(continued from last post)
4. Consider your environment. If you go to a small, private college or university, the "intellectual dick to average Joe" ratio is likely to be depressingly high; the same applies if you're in a humanities or social science class as opposed to a physical science or math class. (In math, the bias apparently reverses and you may be ridiculed for admitting to not loathing the subject and all those who may be associated with it; don't ask me why.) The key is to recognize that said dick's main skill lies in spinning a web of bullshit to makes himself (and they are predominantly male) look smart. Observe the number of times he asks a question in class and the professor pauses and thinks for a while before answering; nine times out of ten, the professor is either trying to think of a way to answer the question without revealing the fact that it was a dumb question.
(On second thought, sitting around trying to prove that these people are faking it is probably a little petty on my part. The key point here is that there are oodles of people who go to great lengths to exaggerate their intelligence; don't assume that someone is smart just because they look and sound the part, and don't think that you're dumb because you disagree with or don't understand someone with real or imagined intelligence.)
5. Start learning about something you enjoy. Chances are the people who seem to instantly understand everything the professor says are those incorrigible forward-thinkers (no offense, you guys) who have known what they wanted to do with their lives from day one and set about it as soon as they could. (I'm convinced that all pre-med and pre-law students are like this.) If you're like me and haven't a clue as to what you want to do with your life, then next semester, take an introductory class in every subject you don't hate (and maybe even one you do) and pursue the one you like the best. Don't worry if you don't have any skill at it; just desire is usually enough to get you through a bachelor's degree, and once you get a job the benefits of doing something you enjoy will probably outweigh any disadvantages from not being good at it.
6. Put everything in perspective. Time to come clean; I have been one of those people who sits in the front row, nods at everything the professor says, and makes bad jokes about sex-linked traits during the break in Genetics class. Why do I do it? I have the good fortune to enjoy learning about the subject I'm in and be good at learning about said subject. (In fact, I like it so much I'm probably going to get a Ph.D., become a professor, and earn less than the folks who slogged through it and got a job with their bachelor's degrees.) It may seem like my predisposition is nothing but positives, but the negatives are numerous and insidious (typing this all out has sapped me of the energy I would need to talk about them; if you don't believe me, say so and I'll write you an essay on them when I can get up the nerve). You can't force yourself to enjoy anything, and if you try, you're probably ignoring your potential to be good at something you do enjoy.
Hope this helps.