Woof has several good points.
Efforts at suppressing emotions generally do more harm than good. I used to bottle up anger and then lose it in a seriously disproportionate way. Those on the recieving end could care less that 20 little things had preceded my blow-up. This is especially true of my family. Keeping it bottled up was easier on those around me, but I started feeling like my brain was wrapped in cotton. It was as if by muting anger, I muted every other feeling too.
For me, I did some counseling. I had trouble getting over my inherent distrust, but my employer "suggested" it. It was like a huge knot in my skull got untangled a little at a time. I began to recognize that I had many options in a given situation. In other words, "auto-pilot" conditioning didn't have to be the only option.
Now, I do OK in low stress situations, and for some reason I do great in high stress situations (I think its' what soldiers and athletes refer to as "situational awareness" or being "in the zone")
It's the ordinary, every day, "medium stress" situations that get me. If I am not paying attention and something catches me by surprise, or if someone goes off on me because they are having a bad day, then, the genie is out of the bottle. More often than not, I do OK, but not always. When I do lose it, I have learned to say I'm sorry, without telling my life story.
Woof mentioned vitamin B-12. I have had health nut friends mention this to me. I don't know, but for me a good nights sleep can do wonders, though I often sleep less than I need. Proper nutrition (another rarity) also helps. Vitamin supplements seem like a prudent option.
Years ago, I started jogging. Once I got a bit of conditioning, I found that an easy run allowed me to think through situations and see new options. Whether the cardio condidtioning improved oxygen to the brain or the endorphins were the cause, I can't say. I did feel happier, more focused, and less easily upset.
I'll be the first to admit that it's a pain to exercise regularly, especially for a closet non-conformist. But, it helps me, when I can make myself do it.
Case in point: some time ago, my youngest son, told me, "Daddy, you used to get really mad and stay that way a long time. Now you get a little mad for a little while. I like you much better this way". The truth does hurt on occasion.
Several Posters have mentioned fear of anger to the point of withdrawal. I know of several folks from the real world who suffered the same problem. Any anger displayed in thier direction caused them to freeze and withdraw. Psycho bosses can take this behavior as the perfect excuse to yell more ("And Another Thing!...).The self recrimination and depression can be destructive. Anger must be dealt with, whether it's ours or someone elses.
Years back a woman I knew had a tendency to shut down and withdraw when anyone got angry with her She found that bad things kept coming her way. It was like an invisible "Kick-Me" sign was taped to her back. After she was nearly assualted in a laundromat, she took a self defense class. The program was called "Model Mugging" They literally practiced defending from attacks - verbal and physical. It's intensive, and might be hard for some to deal with the "practice" when they role-play a mugger or rapist screaming and swearing in your face. They do in fact use a form of "Operant Conditioning" but in a more appropriate way. She explained it once to me, and it made perfect sense, but I lack the memory cells to repeat it. When she tried to explain that what she learned is now "automatic - not in my head - in my spine", I understood. The instructor was a former military man and retired cop who felt the need to help abused women take back thier power.
She learned how to feign submission to gain tactical surprise, retreat when appropriate, verbally posture to make would-be attackers pause, and when/how to fight. They practice holding thier ground, countering verbal attacks, and other self protecting behaviors to assess and defuse a potential threat. If they decide that they need to fight, they fight full throttle.
If you are a wise-ass drunk with a big mouth and grabby hands on the subway, God help you.
I was able to watch her graduation video. Screaming "Dial 911!", She laid a shot on a well padded Karate instructor that lifted him 18 inches off the ground - both fists under the chin and one knee to the balls - this guy was in serious pain through 3 inches of padding. 180 pounds of attacker knocked flat by 110 pounds of femine aggression, precisely and devastatingly applied. In perfect street fighter fashion, she circled around to the head of her downed attacker, just out of reach, but ready to kick, knee or elbow his skull to bits if he opted to get up. Her girlfriends on the side lines cheered her on, yelling things like "Eyes! EYES! Jamb your thumbs into his EYES!" From time to time, I imagine new girls on front row doing this to some ass on the rap stool.
I can tell you this - the change in demeanor, body lanquage and self esteem this petite woman experienced was simply amazing. She learned to walk "heads up" and widen her "circle of awareness" when on city streets etc. Not only that, but her relationships at home and work improved. She changed companies, has moved up several positions with the new company and is doing well. She's still got the odd, "freak magnet" vibe, but in general the freaks she attracts are less threatening. Amazingly, she says she feels calmer. Something about knowing what she can do if she needs to, keeps her in better balance. So, I married her.