I don't reply to my boyfriend when I am angry, and then my boyfriend will keep sending messages, and then how should I reply to him the next day?

If you are angry because of your boyfriend, then when you reply to him the next day, you can just say who made you angry? Although she sent you a lot of messages, when you reply to him, he will know more clearly that he made you angry. Then, he will apologize to you and care more about you. If you're angry about something else, Then say you didn't look at your cell phone. Just answer according to the situation, don't be so entangled.