I accidentally didn't hold the door for someone behind me so I thought I'd get the next one on my way out. Only the next one was a bit to far away so I held if for a bit uncomfortable waiting for him. He realized I was holding it and said thank you at the exact moment I realized holding the door was weird and let go. By the time I let go he was actually there and the door slammed on him. :'(
I'm a bad giver and comrade.