A moment of reflection can help you recognise the pressure behind a quick yes and make a more honest decision.

Someone asks for your help and you agree before checking your diary. Later, you feel frustrated. You wanted to be generous, but you also needed time that you have now promised away.
It is worth paying attention to that moment between being asked and answering. You may be responding to a real responsibility. You may also be trying to avoid disappointment, disagreement or the discomfort of explaining what you can manage.
A pause can be a practical beginning. Try saying, “Let me check what I can commit to and come back to you.” Then look at your responsibilities, your available time and the help the person is actually asking for.
Ask yourself what you would choose if you were not trying to manage their reaction. Your answer may still be yes. It may be a smaller offer, a different date or a clear no. What matters is that you understand the choice you are making.
If you feel guilty after setting a reasonable limit, give yourself time to understand that feeling before reversing your decision. Notice the belief beneath it. Perhaps you have learned to connect being needed with being valued. That belief deserves honest attention.
Begin with one conversation this week. Make a commitment you can keep, communicate it clearly and let your words reflect your actual capacity.