I fixed a leaky tire for my cousin yesterday that I didn't know was a problem until I got there, but that's an easy one since lots of people carry repair kits and floor jacks and impact guns. or maybe they don't. they should. I also carry a bag just for doing brakes because, yes, I've arrived at someone's house and in conversation they complained of brake squeal and I ended up doing their pads. a bit more of the specialty tools, but that's why I have them if I need them. same with minor drywall repairs. or plumbing. or electrical work.
but the other day I found these on the bottom of the dealership sign and yes, by chance, I had the proper tool. (I forgot to add a quarter for scale, but believe me, those are friggin' giant flathead screws! the bit goes on a half-inch socket)