It is considerate to clean up after yourself.
Noam's shower is broken, so he goes to his neighbor Mark's to ask if he can use his.
Noam wants to get clean.
Noam uses Mark's shower and meticulously tidies up when he's finished.
Noam uses Mark's shower, but leaves his towel on the floor and loose hair in the drain.
Mark is impressed that the bathroom looks better than it did before Noam used it and is willing to let him use it again if he needs to.
Mark is appalled and doesn't let Noam use his shower again.