For me it was purely down to not knowing exactly what I wanted to do with my life at 18 (If I was adamant on being a lawyer/doctor/etc it would have been a different story), and didn't want to spend time and money on doing a degree just for the sake of it.
Well, I think that's another angle on it tbh matey. I'm sure plenty of people don't know what they want to do either at 18, so go to uni because it's the "thing to do". Some may not want something too taxing, which is why we get so many doing degrees that seem somewhat pointless.
If you're going, you should have a plan and take it seriously rather than treating it as 3 years of getting wasted. An old mate of mine got an awful Comp.Sci degree because he was constantly wasted. He ended up doing another course afterwards (can't remember if it was vocational or another degree) to sort his life out when the penny dropped that employers wouldn't give him a second look.


