system
A chat on subreddit /r/pcmasterrace
human
The easiest way to damage a board is actually by dropping something heavy on it which can break the wires inside the PCB even if no visible damage is caused.

Other than that, it's really hard to actually damage a PCB. They bend a lot, are fairly waterproof (don't spill on them while they have power though!), and scratching them even with a knife or a screwdriver takes quite a bit of effort. Even shorting them on purpose isn't guaranteed to kill them!
gpt
Some of the surface mounted components will brake off really easily. So beware.