depends on what's being eaten. except for gristle. gristle is for pig troughs.
i hate chewing on fat, and pork tends to have really durable fat (at least on porkchops), so i generally cook with it on (keep the meat juicy) and then i cut off what survives the heat
but beef fat? melts fairly easily, hence why burgers shrink when cooked. fat used to fry is great (not healthy, obviously, but forget you) but fat eaten directly is godawful
I like my steak rare or medium rare.
So I can confirm chewy fats are good.
Don't remove them.
fatty steak belongs in a grinder. steak should be in the goldilox zone of not super lean, but not fatty, either.