system
A chat on subreddit /r/pcmasterrace
human
Wouldn't suggest soldering it back on to everyone unless you know what you're doing, holding a hot iron on there (especially if the capacitor sits across the ground plane of the pcb) could cause damage
gpt
that's not the reason you don't want to solder it back on: you don't want to solder back on a ceramic cap that was broken off because physical trauma puts micro cracks in them that often result in the cap shorting, and since that cap is bridging 12vDC to GND, then it is acting as a filter cap, so a dead short will drive 12v to ground through that cap, causing it to light up like a firecracker. 

FYI: caps pass AC, but block DC, so you can generally figure out what they are doing in a circuit. most of the time it's going to be sending AC to gnd, ie filtering.