How can I tell the difference between "lovebites" and "warning bites"?

Every now and then, if I'm petting Sabbath, he'll give me a wee nip.  No breaking the skin, nothing painful, I'm not certain if this is a warning or the "lovebite" thing I hear so many cat owners talk about.  Never had this with the last cat, who was old and sort of a layabout.

Tonight, as I was giving Sab his supper, he was snuggling in, getting all excited (god, his food is his life), bunting my nose as he always does, then he inexplicably nipped my nose.  It didn't hurt, although I definitely felt those little teeth.  It's the second time since I've had him that he's done that when he's been bunting at my nose.

I don't really know if this was his warning to "hurry up" the meal, if it was overexcitement (him getting caught in the moment and the excitement of his favourite food) or simply just his affection.  How do you tell the difference when it's gentle biting?

A warning bite would follow with the cat backing away or hissing. A love bite will be followed by purring maybe even licking. These are just love bites. You would have no doubt at all about warning bites trust me 

Good to know lol. sab has never hissed at me but he will give thee bites from time to time and it's usually over stimulation in petting and I get the hint but the nose bite threw me lol. He's not really an aggressive cat at all although he can get sort of affectionately aggressive about food and he has a very strong bunt that can actually push me over.