What do you deal with those guys that seem to know everything?
Haha! I love this question!
No worries. These people will always exist. They seem to be more common in subjects I don't know anything. (Probably because I know those who are in engineering are typically full of it.)
My best advice: Ignore it and maintain confidence. You wouldn't gain admission to college if you weren't smart and hardworking...just like everyone else there.
Yesterday, I was reading that women often underestimate their abilities, for fear of being wrong or not being "good enough." Don't worry, I feel like this ALL of the time....hence why I study so much, hahaha. But honestly, you shouldn't feel this way...example...
Last quarter, I had one of these guys in my classes. He went to every professor office hour, invaded the TA during every TA office hour (I think the TA got sick of it, lol), and looked like he had everything together. The day of the final, I walked into the engineering computer lab on campus. He and another guy were studying for this final. He comes over to ask me a question....and it was one of the most simple concepts from the class! Like, he should have learned it like week 3 or 4...or even earlier with all of the office hours.
It just goes to show: just because one may "seem" like they know everything, doesn't mean they do.
Now go out, and be confident. (Eat some chocolate while you're at it.)