I've been noticing the same problem in myself over the last year or so. Or I should say I've been noticing how deep it goes. I used to think I was a really open-minded person. Now I realize that I'm actually quite impatient and sometimes just downright intolerant. I just don't usually say it out loud.
Mostly I notice it with my partner, at home. If I get mad at her, I will punish her by giving her the silent treatment or cutting myself off from her for the day, knowing that she loves spending time with me and wants to be with me (we live together). I am constantly impatient in public (slow walkers, unpredictable walkers/drivers, long lineups, angry people, all kinds of people). The simplest thing can send me into a rage that sometimes lasts for hours. It has been known to last a day or two.
Sometimes I question if I need something like anger management, or if it's just something else in my life that needs attending to. Then I look at my dad and realize the anger apple didn't fall far from the tree. Either did the coping mechanisms, which I got from my mom. I have OCD, which, as mentioned in an earlier post, probably doesn't help.
Hope you find some relief, Infinite. If I find anything that works in the meantime I'll let you know...