It's rude not to answer a message someone sends you.
Troy's boss messaged him twice within the past hour about coming in to work an extra shift, but Troy is trying to sleep.
Troy wants to go back to sleep.
Troy texts his boss back that he's not able to come in but thanks him for letting him know, then lays back down.
Troy turns the ringer on his phone off, so he doesn't need to read any more messages and goes to sleep.
Troy's boss is understanding and says he will see Troy tomorrow.
Troy's boss is irritated at Troy's lack of communication and considers it against him during performance reviews.