Sometimes we expect other people to do the work for us. We want them to sense when we’re tired, when we’re overcommitted, when we’re not in the mood. But they’re not in your head. If you don’t speak up, they’ll assume everything’s fine.
Your limits are your responsibility. If someone crosses them after you’ve clearly stated them, that’s different. But if you never said no, or if you said yes hoping they’d just know how reluctant you were, you’re setting them up to disappoint you. Clear is kind. Honest is respectful. Saying no when you mean it is not rude.