Pretty common. Experimentally, it seems the implicit formula many use for IM is something like

Fewer than K words + a period = probability P(deliberately curt) = 50%, where K is at least 5, and P increases logarithmically as K approaches 1.

Which is how, to someone using this formula internally, “Great.” can denote exasperation, “Thanks.” can imply strained manners, and so forth 🤷