Sure, I'll bite.
OP, I'm assuming that you're asking everyone what have been the greatest difficulties/pitfalls they've faced so you can prepare yourself for them. Just remember, it's all cliche until it happens to you.
Major problems premed's face because they're so obsessed with getting in
1. They trust the grape vine too much. It's a tangled mass of conflicting advice filled with uncertain insecure people that are going to freak you out. Because they're freaking out...constantly. They come in different varieties from the guy who is constantly asking "what do you think they REALLY want from us?" 100X a day to the peacocks who are constantly fluffing their ECs and grades to let everyone know they're good enough. Where are you supposed to go to get honest advice that isn't tainted by bs? I don't know. The lesson is, take it with a grain of salt.
2. They are forced to reflect on why the hell they're trying to become a doctor despite the crap they'll go through. Often this freaks a lot of people out because when they look inside...they find an answer they really don't like or an answer that adcoms wouldn't like. The whole doctor thing and admissions process? It's designed to make you question yourself. It's designed to make you feel like you are not good enough because there are better candidates, because the field of medicine Deserves better, more altruistic or less naively idealistic people than yourself. Reflect on your reasons, but don't over scrutinize yourself. Don't get caught up in becoming obsessed with what some person you haven't met thinks of you. Oh, and while you're reflecting come up with a damn backup plan.
3. B!tchy PIs, volunteer coordinators, doctors you shadow, teachers etc. really aren't that big of a deal in the long term. It's your crazy neurotic attitude that thinks that everything must be perfect the first time through that will stab you in the butt every time. That's what causes burn out. You must be resilient and shed the need for constant reassurance from all of these 'higher ups'. Be open to finding someone else for your LOR. Get friends who aren't premeds. Talking about zombie apocalypses isn't a bad way to get your mind off of the small stuff.
Really, the only thing I wished I could change about undergrad? Getting a meal plan. That rotten food gives you diarrhea. Me acting like a neurotic **** about the app process was the only thing that hurt me in the end. However, even if I had someone to tell me I was a neurotic **** at the time, it's not like I could have internalized that. You just have to learn to let it go on your own terms.
Summary, the biggest problem is you. Aww, next we can talk about the true meaning of friendship and the power of heart. Yeah I said it was going to be cliche. Best of luck.
