I do that a bunch, though I have found it's mostly in relation to things I feel really strongly about (or are very important to me), but also feel an incredible amount of shame around (or fear judgement about it). Like for mastadon and nervous puppy, quiet was always the safer option growing up. Now, when there's something that scares me to talk about, I get incredibly quiet and still. Then I brush off what I was going to say with "it's stupid" or "it's not important"...