I won my first FFA Deathmatch game a little while ago. :O
I've played McCree exclusively in FFA since the mode was first patched in, despite him being at a disadvantage in FFA and despite my being a terrible shot, because I like the character and because I don't particularly care about winning, just the XP. I'd say 2/3 of the time I'm trying to do just enough to not get kicked for inactivity, roaming the map throwing flashbangs and widely missing shots while getting killed with one eye on the TV; the other 1/3 finds me trying to crack the top 4 and usually failing, because Flash-Fan and bad aim only gets you so far with one eye on the TV and a map full of Junkrats, Widowmakers and Soldiers.
This time though, was different. Several minutes into the match I heard the announcer and thought "holy crap, I'VE taken the lead?!?" Then, as I moved through the map I noticed that most of my opponents were soft targets: multiple Tracers, a Mercy, a Ana, only one Junkrat, only one Soldier, etc. "No tanks? No Mei?" I thought. "Waitaminute, I might actually have a shot at this." And I did! I even got PotG, with a Deadeye on a group of players in the tunnels underground, so caught up in their duel they couldn't escape.
It was a strange feeling to actually win a match.