To be honest I don't really make up backstories for my characters I prefer to play with intent and have that shape the character over multiple rounds. Like at some point my sec lizard character went to deal with gorillas at a banana anom and got his arm torn off so now I play him with a prosthesis.
I remember a few good moments, like a long time ago on Starlight there was this moth who caused trouble whether antag or not, and at some point in a shift with the same lizard secoff we were under a lot of pressure, hos was busy handling civil disputes between the chef and another member of crew, warden was ssd, and suddenly we get a call for nukies. The armory is locked, I'm currently processing that same moth for repeat offenses and when I see the station is about to collapse I whisper to him "I won't put you in brig, this is the end for all of us so I'm making sure you go first". Drag him screaming to the chapel and sacrifice him on the altar. What's hilarious is it was just a lone op nukie who did almost nothing, but then we still all died a few minutes later with a zombie outbreak.
More recently on Goob, one of my first rounds as RD with my "not SSJ 3" character I'm going around making anoms destroying anoms whatever then a gravity anom I had left unattended just a bit too long almost goes crit, so I rush in, the whole time I got a guy after me calling "RD RD" but I don't have time to respond, I get irradiated, I drag the APE behind me, get it in position, I don't remember the containment particle so I look it up and scream over comms so someone can take care of it. In the end it decays and all is well, and there's still this guy calling for me "Guess what ?" I say "What?" "Chicken butt" and he INSTANTLY turns me into swiss cheese with an smg. Later into the round he gets a bluespace anom and I'm like "Why wouldn't I just blow it up ?" he was a chemist so in the end the CMO convinces me to actually get him rid of it.