Not jungler, but here's a story:

Some months ago, I was playing my (then) main Soraka (before the changes to her). This was a solo unranked game... learned my lesson by now. On top lane we were up against a Cho' and a Nunu up for a jungle gank. My carry, Yi, gets harassed by (a much better) Cho' to about 10-15% hp. My heal CD is finally up (some 5-7 secs if memory serves me) so I heal for what I can (this is level 4 or 5, so no ulti) giving him some 50-70 hp iirc. Any rational player would see this as a "dude, b the eff home, I just gave you a window of opportunity: two more hits and you're b-ing the hard way" moment. Instead, he goes back to fight an almost full-strength Cho' getting trapped between him and a very warded and visible Nunu stalking from the bush. What followed was an almost instakill and a "ffs, noob Soraka" in the chat.