It seems if they only draw blood if you have pissed them off!!!

If they bite lightly it is their way of stating I do not like what your during while petting or holding them!!!

When playing their are two types one they lightly grab bite and release quickly!!!

The other they grab bite by not bearing down it just enough to let you notice either I am playing or telling you to stop immediately!!!

If they bite and draw blood you are directly crossing their threshold of pain, holding them too tight, or scaring them excessively!!!

Some cats are just mean by personality or they just do not like you period!!!

People laugh at the cute little kitten play fighting and biting and then wonder why their grown up cat bites and rabbit kicks. As people say, watching for signs and quitting what you're doing is best. If my cats get aggressive I just move away, take my hand away, say OUCH, and then ignore them. They will come back when they are settled down.

hard tp say but multi different reasons seems like the right answer

So in short the answer is, as usual. “We don’t know”

My partner taught me to look for tail tapping that usually came before a hand grab. Once you knew the signs ours was quite easy to work out. But then he’d want to sleep on you lap after pats

One of our first cats fell to us because she was a fierce biter. I always assumed that the reason for the aggressions was that her previous staff had mistreated her “in fun”. Things like using the vacuum cleaner on her, throwing her into (across actually) the pool, and hitting squash balls her way. Combined with the kind of play that his Great Dane had positively craved. Lots of calm interactions and training led her to realize that petting and or snuggling was available without biting and that biting was OK but she would be biting a pair of 1/4” welding gauntlets. She never got to like vacuums but then no cat really does. She spent the rest of her life as a beloved, sweet-tempered, soul.

I always thought it was love bites. I haven't had one of my cats do that in years.