I am good-tempered. Generally I am understanding that we all make mistakes, and I am patient if I am inconvenienced. If anything I'm more likely to try to cajole others and help them calm down if it looks like they're getting defensive or upset or they're raising their voice.
I do have limits though. Fairness and truth are very important to me, so if I feel someone is being unappreciative then that can irritate or anger me. Things like guilt-tripping me over not loaning you money this time, complaining that I didn't return a call fast enough or just barging into my house without asking permission would not be cool with me. I tend to be giving, but nobody is entitled to your time, energy and resources. This may not be so much a temper as just having some boundaries.
I try my best to be sensitive to others feelings, so it's not my default to be aggressive and shout, but I'm also going to respond to the vibes you send out. If you are rude, condescending, derogatory and really forceful then all bets are off. I'm not going to let someone just have your way and run over me or others. I don't respect people who bully others, nor do I respect not standing up for yourself.
I wouldn't answer the question if I am quiet with a yes, because I can be very talkative and detail-oriented, especially when I am in the company of people I have known for a long time and/or really like. But I am soft-spoken in the way that I communicate, rather than loud if that is what is meant by quiet. It's not like saying something at a higher volume makes it somehow more substantive. I am not sure if it always translates online because tone is easy to misread, but people who speak with me in person or over the phone at least say that I have a soothing voice, and seem unruffled. I am collected usually, even when it's an emotional discussion.
Yelling at somebody would not help me relieve stress, it would probably cause me to feel more stressed. People who seem full of anger or who lash out quickly and/or inappropriately are not compatible with me. I notice when people sound loud and shrill, and usually it makes me uncomfortable, and I put some distance between that soul and me. It should go without saying that any kind of physical violence to demonstrate your feelings I consider completely unacceptable and abusive, especially when it's directed at our most vulnerable like children, the elderly or animals.