20's easily.
Teens were okay but too many 'life' problems (or what I thought were problems). 20's was a fun decade for me, I managed to get a degree, travel the world a few times, get pissed and not care, had a massive laugh on so many occasions, got engaged, got beaten up by my fiance (lol), met so many amazing people (along with many twats), worked some epic jobs and done some exhilarating things, worked out what I do and don't like and tbh I would not change anything about the last ten years of my life. It has been a riot.
I just hope the next ten are equally as amazing.