I was reading this thread wishing I had a story, and then remembered I do! And it makes my DH look pretty freaking awesome.
We were doing our weekly shop when we came to an aisle where there was a spillage of sugar, a member of staff with Down's Syndrome was standing in front of the spill telling people to be careful.
As we got to the top of the aisle we heard someone shouting and turned around to see another member of staff SCREAMING at the poor bloke "why don't you bloody move and DO something instead of standing around looking useless." Now DH happened to work for this chain of supermarkets at the time in another branch, so knew fine well when you have a spillage, the course of action is to stand next to it to warn customers until you can find someone else to get one of the wee yellow caution signs.
Before I knew what was happening, DH stormed over to this bloke and told him to pack it in, that the guy didn't deserve to be reprimanded like that because he wasn't doing anything wrong, and even if he DID it wasn't appropriate to shout at a member of staff like that. He also suggested that instead of standing here screaming, he also do something useful and help clear up the mess.
Shouty man stomped off and DH checked the poor guy was okay - he wasn't, he was really upset by this point and just kept saying "thank you, thank you" bless him. A manager must have heard the commotion because one came round the corner to find out what was going on, DH filled him in, the manager thanked him for stepping in and promised he would resolve the issue.