"get the gullet" lotta times the round file will sorta walk up and leave you withe a negative rake on the top plate, it will still cut, sorta, but not nearly as aggressive, that our you need to hit the rakers a little better. File when the saw is dull, not just for every tank or whatever, Hell I cut 4-6 hours a day and I've gotten a week out of a chain before (its rare... cause I still find dirt now and then)
you likely won't notice teef being broken, worst case one gets stuck in the wood and manages to take a few more with it. You should be wearing eye protection when running a saw so that would be the only soft squishy bit that would even remotely be in danger of broken teeth.
I have had every tooth on one side of chain come off in a single cut... not good... that damned tree tried to kill me as it was.. but I did manage to cut it up even with only one side working, I didn't really notice until I started limbing and it just wasn't doin the job...
Its a lot like getting hit in the face by something bigger and harder then you... teeth come out in pieces and you don't notice for a little while until its dinner time and it hurts like a MOFO for some strange reason... or if you whistle.. that can be pretty damned bad lol, cold air across a bunch of freshly exposed and frightened nerve endings...