Vindictive nails
There is a special type of person who just likes to wander through life making it worse for everyone around them. Often these are the sort of people who don’t think about how their actions affect other people and consider servers and store assistants to be beneath them. This all adds up to situations like the one in this photo.
Someone, or a few someone’s, decided it would be funny to cover the shelves in hard-to-remove nail polish. It might seem a tiny bit of vandalism, but this would have resulted in a good few hours of work for someone to clean up, or even a costly replacement of the shelving units. Either way, it’s a really rude thing to do.