Collards are 90% awful, 1-10% heaven IMHO.
Few up where I live know how to prepare them properly. (Low and slow, transfer pork flavor then discard tasteless parts, use real cider vinegar to cut bitterness - mmm)
“use real cider vinegar to cut bitterness...)
My wife says give a 1/4 cup of sugar a try en lieu of the cider vinegar.
Most European and American greens (kale, arugula, collard, etc) are awful.
Go to a local Asian market to get good-tasting greens.