Yeah... I get too opinionated too.. but I usually dont' say much and I add stuff like afterwards like "but yeah I liked" something else about the thing.
One time my brother's old band had a new song, and he sent me it, and I thought it was like a joke song like purposely kind of a joke, and without knowing it wasn't, I said stuff about it like how it sounds, it wasn't too harsh I don't think, but I did say stuff more like really mocking of it. I still feel bad about that, even though later when it was done I really liked it and it was actually one of my favorite songs of theirs.
But yeah sometimes I'll say things and regret them, even if it's stuff that's not actually mean, just more negative.