A lot of guns have been screwed up by amateur trigger jobs, some made very unsafe.
Oh, I'm sure that some can do it on their own. Other people (even "professionals") screw it up.
First thing I would suggest is: shoot the heck out of the gun! I have a Springfield Loaded 1911 (9mm) that initially was a little rough. After about 500 rounds, it's a good trigger.
OTOH, some guns should have never been left out of the factory! I had two Browning High Powers a dozen+ years ago that had triggers so bad that I sometimes thought the safety was on! The worst purchases I ever made. Before I reached the 500 round mark, the front sight broke off
My FEG clone is a lot better (and better priced).
Ken