I try not to do it and I have improved. Because I was made to be scared of interrupting other people.
I reduce my speaking time, usually. So I interrupt people less and can still talk.
Sometimes I will not react to what another person has said at all because I don't know what they expect me to answer. I think about a possible answer, but then think that they will not want to hear it. I interrupt myself in my head before I can say anything.
This is not a satisfactory solution, but I do not know an alternative. ^^
Comments on your school report can make you feel really bad about yourself. Or people who tell you to shut up. ^^ "OK then, I will try to speak as little as possible". That is my strategy, but sometimes I can't help but interrupt people.
This is why you retreat and refuse to join in conversations unless it is really necessary. You are afraid of saying the wrong thing, saying too much and saying something irrelevant.
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EXPANDED CIRCLE OF FIFTHS
"It's how they see things. It's a way of bringing class to an environment, and I say that pejoratively because, obviously, good music is good music however it's created, however it's motivated." - Thomas Newman