stop explaining myself

I’ve realised I have a tendency to explain everything I do. Why I want to eat something, why I said this and that, why I’m wearing this today, even why I want to return something to a shop. Normally, people would say “I’d like to return these shoes”, but in my case I feel guilty for not saying they’re too small or whatever, just insane. I annoy even myself by explaining my friends why I feel that way or why I think something is right or wrong. It kind of makes me think I don’t believe in myself if I have to sort of defend myself to others. Maybe understanding my actions and saying it aloud helps me to get rid of my problem.