I've never lost a Deer. I was taught to only take the shot if you are sure that you can deliver a clean one shot kill. I hunted for 10 or 12 years before I connected. I seen plenty of Deer and Elk during that time but no good shots IMO. I've been told I could have hit that deer at 300 yds and only hesitated, but I hadn't practiced at that distance so couldn't reliably take the shot. I took ribbing for awhile and I am 2 for 2 now. Curiously, the guy that said I should've taken that long shot has lost 2 deer that I know of and who knows haw many others that he wont talk about? He doesn't rib me anymore.
I have lost some rabbits here and there.