Yep, they can get a little bit of an attitude.I know that look. Had one pissed off cow run 300 yards down the middle of the Lower Madison at me while fishing one year.
It is possible to sprint in waders.
I have only deployed bear spray once, but it was on a young bull. Glad I was set up behind a tree, but at 20' he wanted a piece of me and my yelling and waving arms was not working.