I've had a few good stories from playing Security. (BRAG)Like the several times I've discovered cultists super early on by checking for falsewalls in maint.(/BRAG)
But my absolute favorite story from playing Security, the one that I share even with friends who aren't familiar with SS13, is from a round where I was playing Detective.
Playing as my character, Maxwell Edison, I decided to hit the bar and try to outdrink my "sober" gene. As I downed more and more alcohol I noticed that the drunk speech effect, where it randomly capitalizes and misspells words in your speech, is coming and going with everything I say. Eventually I get called to the brig for something and on my way over I get that hazy screen overlay that happens when you're super drunk. The Captain, HoS, and Warden are all there, and they take note of my strange speech patterns. The HoS asks, "Detective Edison, are you drunk?" To which I reply, "No," and then immediately pass out drunk.
For reals, it couldn't have been timed more perfectly if I had planned it.