First year of university. Lived on campus as an 18 year old, and I wasn't mature enough to handle that. I didn't study, I played video games, hung out with friends and failed a lot of my classes. I was essentially booted out, went down to a college with a bruised ego and worked my way back up, and got re-accepted to the same university that kicked me out. Haven't come close to failing anything since then (except Medieval Japan - I was never really interested in it, just took it because I needed one more arts course that semester).
On a side note: WTF is up with the multi (multi-multi-multi-....) quoting?