It helps to consider that my neighborhood is semiurban, and has been squirrel feeders since before my folks bought in in the '60s to the little critters have Learned Behavior handed down across generations about "we eat better if we play nice with the big uglies and keep them amused."

Lefty HAS grazed my fingernail ONCE by accident, just enough to be a scratch and I do worse with my nailclippers, and even then he got this big-eyed look about "OHSHIT what did I just do?!" and swiftly backed off. The occasional teeth barely grazing skin when going for a nut, but again never bit down and always pulled back as soon as they realize "oops that's no peanut."
Good luck getting a wild squirrel fixed.

There's another male around, bigger and aggressive, that I'm much more worried about, but even he knows there's something MUCH bigger and more Bad News that he would be wise to stay on the good side of after seeing me Super-Soaker a couple crows.