If you've got talent, people want more of you. They ask you for this or that or the other thing. They ask nicely. They will benefit from the insight you can give them.
The choice: You can dissipate your gift by making the people with the loudest requests temporarily happy, or you can change the world by saying 'no' often.
You can say no with respect, you can say no promptly and you can say no with a lead to someone who might say yes. But just saying yes because you can't bear the short-term pain of saying no is not going to help you do the work.
Saying no to loud people gives you the resources to say yes to important opportunities.