Seeing sparks
Electricity isn’t something you should be messing around with unless you’re qualified. A hugely powerful and dangerous mains circuit shouldn’t be touched by anyone other than a professional. So, when this tenant started to see sparks coming from their wall socket, they contacted their landlord.
Nothing happened for weeks, however, and so the tenant decided to take a look himself. It didn’t take long to figure out what the problem was, as the sheer amount of dust and debris behind the panel is ridiculous, and a fire hazard. This is not how your electric sockets should look.