Years ago, I used to vent my frustration on our pet cats when they did minor annoying things. Never anything injurious, but picking them up, yelling and throwing them across the room into a soft chair. It was like an uncontrollable rage, tempered only by the thought of preventing permanent injury.
I constantly thought of myself as a monster and feared what I might do to my kids when I started a family. I was also afraid of my live-in girlfriend finding out.
Thank goodness, I've worked through it and learned not to punish innocent beings for my inability to cope with pressure. I've never admitted this to anybody -- other than now, anonymously -- and I probably never will again.