At my previous job where I dealt with customers I’d have still gone in to work as usual and waited on people. The pleasant or at least tolerable customers would have been treated properly since I couldn’t in good conscience treat them poorly if they didn’t deserve it. Once some rude prick came up to me and started bitching or making unreasonable demands I’d finally get the satisfaction of being rude back to them and telling them to f**k off and go to our competitor if they don’t like it. I’d keep this up until the manager fired me. Before leaving the store I would have purposely triggered the dozen or so security alarms in the electronics department (they were very loud and shrill, annoying as hell, so imagine 12+ of them going off at the same time). I’d get in one last shot and make a very obnoxious and rude announcement over the store’s intercom before running out the door.
Having my work clothes still in my possession and having the money to travel to other cities, every now and then while in such cities I’d go into such stores dressed as and acting like one of their employees and repeat the same stunt with any rude customers I encountered until I got kicked out of the store. That would be so fun!
At my very first job, which was fast food, I’d probably do all of the above, but since I also worked with a major prick of a manager I also would have trashed the whole kitchen (knocking things over, shutting off equipment, knocking things off of shelves, etc.) I’d grab a couple ketchup bottles on my way out and then squirt their contents all over the manager’s car before fleeing the scene.
I probably wouldn’t actually have taken things this far, but some days I left so pissed off at customers and managers the thought of such antics crossed my mind several times.
At my present job there aren’t any people I dislike so much that I’d try to sabotage them or their projects and I’d probably just bow out gracefully and give adequate notice out of courtesy.