Male cats tend to do that for some odd reason, whether they're fixed or not. All male cats I've had or known of do that crap. Which is why I got a female cat this last time... and she doesn't do that.
My female pees when she is very angry - including 3 times on me over the 7 years I've had her. She is one intense kitty. I apparently really ticked her off one night, then was lying back on my bed reading a book. I felt her come over, then something felt weird. I looked down and she stared right into my eyes while she peed on my feet.
There was/is nothing wrong with her physically (I was working as a vet tech at the time) and she has 3 litter boxes, all kept very clean. She has zero stress in her life - no kids; the dogs ignore her; I live in a rural area; but she doesn't like change, such as moving the furniture around. The issue resolved when I allowed her to be an indoor/outdoor cat, but she has me well trained. If she wants to go outside, she starts scratching on something, like she's going to pee and I come flying across the room. She hasn't peed on anything for about 5 years, but I'm still paranoid.