This happened to me a few weeks ago.
Rear tyre on the van got a slow puncture. Lived with it thanks to compressor for 3 days but finally had to do something so went to Dodgy tyre sales and got a second hand one for £25. Plenty of tread, looks fine and off we go.
Next day was a busy day for bin cleaning - flat out and at 5.30 with 3 left to do I get a sudden crash from the back van followed by the feeling that I'm waterskiing for about 30 yards. Yes, wheel had dropped off. Hadn't been tightened by on properly by Dodgy tyres and my fault for not checking. Wheel is wedged inside the well. No jack (van didn't come with one) and no hope. Worst thing was that tomorrow is also a huge day for me and I'm looking at losing it. (Bins aren't like windows. If you miss them on Friday you can't come back and do them on Monday cos they're filling up again).
Phoned Green Flag and stood glumly next to the van when the other bin cleaner in town suddenly turns up. Amazingly I'd broken down 50 yards from his house and his wife had spotted me. The first thing he did was ask me how many bins I had left to clean. I told him 3. He sent his oppo back to the house to fetch his van and take me out to clean them. Meanwhile he's somehow managed to get my van up with a trolley jack, onto house bricks and then jacked up again high enough to get the wheel back on (he's a mechanic by trade). It took him 45 minutes and he was covered in oil, grease and dust when he'd finished. Not to mention the fact that he was lying under a van with half a ton of water in it and that the bricks could have given way at any stage (two were split in half when he took them out).
So in other words, this is my competitor who put me back on the road and saved Friday for me. Had Green Flag taken the van to the garage God knows when I'd have got it back.
His two young kids were watching at the end and when he'd finished I got my wallet out. "I don't want anything" he said. "Just give the kids a fiver each."
We've always chatted in the past and never been any rivalry but nothing would have let me think he would do something so kind when I was in the poop.
What a great bloke.