There are many things that can go wrong in college! But, just like Mdmumtazmehdi said, college is meant to be enjoyed also. It will be one of the best times in your life! Remember to always have your fun.
- just like deefoster said, depression. Everything is new in college and sometimes difficult to adapt to.
- difficulty learning. This is a big one. In college we need to learn how to learn. While in high college there may have been some teacher there to hold your hand, in college you're on your own. You decide how much you want to learn and what is the best way to do it.
- loss of meaningful relationships. Romantic relationships are being put to the test during college because of increased temptation for both, distance and busy schedules. Long-time friends might also lose touch. Family reunions will definitely be different.
- competition. Every college in the world has its fair share of over-competitive students who may do anything to get ahead, including abusing you for no reason(psychological abuse mostly). Always keep your eyes open for selfish behaviour and try not to associate with those types.
You actually posted a very interesting question! I would like to get a hub going, because the topic is very important! Feel free to contribute.