My cat adopted me as a feral kitten. MOST of the time she is a great companion, but when she has had enough petting, or being ignored, or gets a wild hair, she will hiss and bite - from placid to lunatic in a few seconds.
Since she was half-eaten by a pit bull and has seizures, I have to accept that it is just one of the ways she communicates, and nothing malicious. Rabies is a HUGE problem near me, and while I may slip some food out to strays, I could not risk adopting one. In the past months, rabid bobcats, foxes, and a wild hog have all attacked people with no provocation or forewarning. Kinda scary.