It has been my experience that MANY people on this site (not saying you, Cadet) pay lip service to "setting boundaries." I have found that that once you start actually pointing out where people need to do so, you often get a lot of flak from the MLC crowd.
To paraphrase that great marital sage, Jerry Seinfeld: I'm pretty sure that the ENFORCING of the boundary, is the most important part OF the boundary."
Starsky
There have been more recent discussions about boundaries and the different perspectives on them with one camp seeing misunderstanding in boundaries which as applied appear as controlling vs. the other camp seeing misunderstanding in boundaries which as applied appear as doormat.