This is kind of a long one:
Sophomore year I was in this French Literature class (taught in French, not French literature translated and taught in English, a minor point but semi-important). It was honors level so there were only about 8 people or so in the class. Enter student "X." We got to talking before class one day and we discovered that we were both pre-med. She started asking me about applying to med school and stuff, and asked me if medical schools required calculus because she hadn't taken it. I think I replied something along the lines of I don't know, I think some might and some don't, it depends on the school, and that it wouldn't hurt to take it just in case you end up applying somewhere that required it. She snapped back that no, they don't require calculus (which is wrong anyway, some schools do). I wanted to ask her why she even bothered asking if she already knew the answer, but I shrugged it off. Then we got to talking about what other classes we were taking that semester and she said she was taking first semester organic chemistry. I told her how I had taken that last semester and wished her luck because I found it difficult. She then proceeded to brag about how she hired herself a private tutor so she can get up at 5 am every morning to study and how she refuses to study with anyone in her lecture so that helping them doesn't hurt the curve for her. As if helping them was only a one way street and that she didn't stand to benefit at all. It was then I knew I had a gunner on my hands. She would come in and brag how she spent three hours translating the short, 16-line poem we were assigned for the French Lit, making sure she knew every possible translation of every possible word. She would always come up with ridiculous analyses for the pieces we were reading to seem deep and intellectual, when it really just left the class and the professor wondering if she even read the same piece that we did. She even had the audacity to remark aloud "how bad some people's French accents are in this class." And like I said, this class only had 8 people in it, so everyone heard her. She would always brag about how much she studied as if that somehow directly translated into her being a better student than everyone else, even though I know she wasn't getting all A's on her quizzes and papers like she'd lead you to believe. Anyway, several weeks into the class I noticed her attendance getting spottier and spottier until she just didn't show up anymore. Eventually I asked the professor where she was, thinking maybe she was really sick or something, and the professor responded that she had dropped the class. Apparently her hours upon hours of studying and translating, superior analyses, and her impeccable accent didn't translate into the A she thought she should have (from what I could gather from her attitude she's the type who'd drop a class in fear that she'd get anything less than an A).
The next semester she was in a large lecture class that I was also in. She wasn't as insufferable as she was in the French class, maybe because I made sure to sit as far away from her as possible, but she did pull the old "ask the professor questions, and phrase them in a way that is evident that I already know the answer to them, and thus are asking them just for attention" trick a time or two.
Fast forward to senior year, and I'm hanging out with a few friends. Two of them are in the same medical ethics class, and they are complaining about this annoying classmate of theirs who always twists their readings to mean something completely obscure that has no basis in the text, just to seem smarter than everyone else. I asked them if this student's name was "X" (it was an uncommon name) and to our mutual shock it was the same person. We spent the rest of the semester swapping ridiculous "X" stories. Apparently old habits die hard.
Worst part is she got accepted to the same med school I'm attending next year. I pray she chooses to go somewhere else next year, I don't know if I could handle her for four more years. But I guess if its not her it'll be someone else right? At least I'd know which one to avoid.