Wow! Your experience hits the bulls eye because my number one regret is so similar. Having said that here goes the list:
1) Taking academics and GPA waaay too seriously. Sure I wanted to do double degree (or double major as they call it now) but trying to get As in all classes while overloading every single semester did not leave much time to do anything else (at least not very well). I should have focused on just one degree (with the other as a minor or sth.) and would have a had great time putting time on my various interests.
2) Trying too hard to avoid personal debt. Sure working in that low wage job for crazy number of hours did save me couple of thousand bucks, but now all that effort for so little value sounds laughable

3) Not spending enough time with friends/family etc... (now that I think about it was all due to number 1 and 2, but oh well..)
Not to go all Dr Phil here but damn that was therapeutic!!
liubhs02
I don't like to live with regrets, so I only have one regret: focusing too much on grades and not enough on enjoying life.
The difference between a 3.95 and a 3.5 is only 0.45 points, but that's hell of a lot more Bs. Making half Bs and half As is exponentially easier than trying to make all As. Because of this I didn't get to experience the culture that my college town has to offer, which is renowned for its live music, eclectic population, and diverse culture. Only after I graduated did I find more time to experience life. But I'm glad for that regret, because it changed my outlook on life. The ultimate goal in life for me is to be happy and not make money. I find it ironic that many people work at jobs they dislike so they can have a 2-week vacation and retire at the end of their life. I decided to enjoy everyday of my life by working only at jobs that I like, even if it makes considerably less money. Life is too short to waste my precious youth.