What mistake do college students make picking a university?

Oh boy, there are tons. Essentially, they revolve around the matching between your personality (which will evolve), your desired career path (which will also evolve), and the school's student culture (which can evolve, but less likely).

  • Picking a university solely to attend a prestigious school: Ignoring the magical spark that is ignited when they visit lesser ranked schools, not considering the student culture/atmosphere, solely attending for the name of the institution. Harvard, MIT, and Duke have vastly different student cultures, and this caters to various types of preferences.
  • Attending a school for its generous financial aid: Limiting financial debt is vital, but picking a university solely on its financial aid is quite foolish. Apart from ignoring the campus atmosphere, some students pick schools which would hinder their career paths, simply to save money in the short term. If you get admitted to Columbia or NYU, and dream of working on Wall Street, why would you even consider attending UNC-Greensboro on a full ride? Understand the concept of Return on Investment.
  • Staying home for the wrong reasons: Too many students get convinced by their parents/pressured into staying home, and attending the local university. Although excellence can be obtained anywhere, attending a local university for reasons that are not financial is quite risky. For example, if you dream of working in Silicon Valley, and get admitted to UCSD, staying home in Gainesville, Florida isn't ideal. You can still achieve your dream, but you are renouncing a significantly easier, and far more pleasant path to your goals.
  • Assuming that they will commit to a path from the start: I believe that statistics state a rate of change of major of over 50%. It is risky to attend a university-based solely on the assumption of a chosen career path. One common mistake is staying home, with the assumption that the student will matriculate to medical/law/professional school, hence saving money for the future. Although financially efficient, on paper, there are too many uncertainties tied to this decision.
  • The biggest mistake students make, when picking a university, is not visiting the campuses in a thorough fashion. By thorough, I do mean staying one night on campus, ideally with a host student, and attending a day's worth of class, over the course of two days. You should do this for the schools you are strongly considering. Seriously. Take the time to really understand a school, it is arguably your first major life decision.

Good luck! Your school doesn't define you, but it does define some of the obstacles, and opportunities that will open to you, over the next few years! Choose wisely!

Is healthy eating a bit overrated when it comes to living a long life?

Healthy eating can be overrated. People think organic is much healthier but it is somewhat healthier. Most people are clueless as to what is extremely healthy for us. Organic isn't extremely healthier but it is healthier.Organic may not be really organic. The usda says seedless grapes are organic. The USDA have there own

According to the theory of evolution, why do we die? Not how we die, but either why it is more advantageous to die or why it's impossible to circumvent death despite the inclination to survive.

No.  That is so far from reality that it's hard to even know which mistake to tackle first.Life does not 'choose' to die.  Lifeforms die once they have reproduced.  The entire purpose (if you want to use that expression) of life is to pass on the genes of life. 

What would be a good full body workout for a beginner to the gym?

Great, If your goals are developing overall body fitness and you want to achieve this goal with these above exercises' list, but I suggest you to take certain guidelines that work best on your starting stage. Some exercise programs for beginners have to follow these guidelines;