I had a co-worker that was pretty big, he could tip the machine in our break room over and shake all the goodies out from it. Those chips tasted like victory.
We had some machines at the office that were notorious for stuck bags. I went by the vending area one night and found about an acre of broken glass spread out in front of one of them. I suspect someone tried the punch technique a bit too enthusiastically.
I normally shake the machine by pushing against the top edge. More leverage that way and if the feet are slightly out of adjustment the machine will rock pretty easily.
There was a similar incident at my office, and when the surveillance tapes were reviewed, we found out that an enormous black woman had hit the machine with her enormous black ass and shattered the thing. I probably should have put that on YouTube while I had the chance.
This machine is basically telling you that to use it correctly you have to degenerate into an animal state and attack it. This is a single unit of the man keeping you down.