The difference between living a life of peace and productivity versus a life of stress and resentment could lie in one simple skill: Learning how to say no.

Saying no makes the difference between a packed schedule and an open one. It makes the difference between having too many tasks and having just the right amount. It makes the difference between working crazy hours and hitting deadlines without stress.

But saying no can be tough. You might feel uncomfortable saying no because you worry about upsetting people, looking like you can’t handle your workload, or missing out on opportunities both now and in the future.