My cat has mood swings!

This isn't really an issue, as he's done it his entire life, but I've always been curious as to why he acts like this. My 12-year-old cat Jack will rub up against your legs, purr, and beg you to pet him, but hiss and bat at you when you do. He also likes to hiss and bat at shoes because he's been tripped over so many times from zig-zagging in front of people's feet. Some days he will be extremely affectionate, so I will hold him and pet him, which he loves. However, after a few minutes, he will bite my thumb, hiss, and smack me with his claws. After he is done with his "fits," he goes back to being affectionate! I've always just ignored it, but I just wonder if he's the only cat out there who does this and why he does it. Any opinions are greatly appreciated. Thank you!

Casey, Dippy, Jack, and Boots

There is something known as petting agression. Cats like petting to a certain point--and every cat has a different 'point'. Cues that your cat has reached that point (at least in Ritz' case) include tail swishing. Here is an article about petting agression and here is one about agression in general.
With Ritz I pet her and stop every minute or so and wait until she 'tells' me she wants more (looks adoring at me, rubs her head against my hand).

Thank you! That is very helpful! The funny thing is, Jack acts like he wants more, then, in a New York second, smacks and hisses! He never even shows he's done, haha! I love him though! He usually just goes back to normal after that too! Goofy cat!