AIBU has, over the last ten years, taught me how much most humans hate to be told they ABU.
I have since developed a way to sweeten the pill in real life and imply they ABU but never actually use the phrase YABU.
It helps with people I know, with patient interactions (am doctor) and even once with an unhelpful gentleman with my phone company!
I'm not sure I used the phrase much before, but learning to say it without actually saying it does help me out.