Having tried all three, its a stark difference in how much more social Lemmy is comparatively. Its not even close. Almost all posts I've encountered on lemmy have interaction; whereas, more often than not, posts on the other two platforms have no interaction. Wonder what the driving factor is behind this difference?
The blog style format (post + threaded comments) is a lot more inviting to a conversational style than microblogging. Some Masto instances have very open post character counts but some are much more limiting - as are Bluesky and Xitter. If you're not able to explain your point clearly it hampers the ability to have a decent conversation about it.
Or maybe you're so used to posting on a platform that's bad to hold a conversation on you don't notice when you're part of one on a platform that is good at being conversational on.