Edits should fix things. Typos, bad grammar, bad punctuation, misformmatted code, numbered lists that didn't come out right, and excess chattiness should all be fixed. The too minor reason doesn't refer to the fact that a change is unimportant so much as it does to you left things unfixed.
Some people, perhaps on a campaign for rep from suggested edits, search for things, like "thanks" or a common typo, and fix only that problem. These common mistakes are great ways to find posts with problems, but if the suggester fixes only the thing they searched for, and leaves all the rest untouched, then the edit is too minor.
So, should your edit that removed chattiness be approved? If the post is now perfect, yes, probably. If the post is still in need of an edit, definitely not. For the "now perfect" case, some reviewers ask if the edit was really needed (some people change can't to cannot or might to could, that sort of thing, which is pretty pointless really) or if it was polite (removing only Thanks from an otherwise perfect post can offend some users) and will reject even if the post was left perfect.
Of course, balancing that are the robo reviewers who approve everything because approving is quicker than rejecting (no need to choose a reason) and they're grinding for a badge. It's hard to draw good conclusions about how to suggest edits in an environment where you might get positive feedback for wrong actions. But that's where we find ourselves.