I had a phase in my 20s where I "hardened" somewhat toward others. Before that, I always loved everyone and gave people the benefit of the doubt even if they were doing stupid things or whatever. I really just accepted everyone openly. During a few years in my early 20s I started to be more judgmental toward people. Once I realized this was happening it really made me sad and I consciously tried to limit it.
Also, when I was younger I was more into "following my heart" when it came to career and moving from place to place, etc. In my mid 20s I had a series of moves and things that really just didn't work out at all and was more disrupting/uprooting than I would have like with almost no benefit. It was depressing because I didn't feel like anywhere was "home" until just about 2 years ago (I am 30 now) even though I've lived most of my life within 2 hours of where I grew up. Anyway, after that experience in my mid 20s I value stability so much more now and it has gotten rid of some of my impulsiveness.