I would say, damaging a flashlight :frowning:
Yesterday I was attempting at modding my Olight S1R Baton I with a LED swap and ended up damaging something, as now the Moonlight mode doesn’t work properly. Other lights, drivers, leds and switches have been damaged along the way.

BUT, as some have already mentioned, spending money and getting addicted is the worse evil you’ll find existing when you have been bitten the “modding” vampire :smiley: