A gross shared fridge is a lesson in how standards fall apart when they belong to nobody.

Shared things decay when responsibility is spread too thin. If a job belongs to everyone, nobody is the person it belongs to, so each of you waits for someone else and the fridge quietly becomes a problem. It is not that people are lazy; it is that nobody was named. Standards need an owner or they sink to the lowest level anyone will tolerate.

In whatever shared space you are in, take one job and claim it out loud. The bins, the dishes, the shared drive. Naming it makes the standard real, and other people usually pick up the rest.