Don't do anything you're going to be resentful for.

That's the best advice anybody ever gave me, and while it may seem obvious to some of you, for me it was life changing.

I used to have a very difficult time saying no. I was so afraid I'd upset people by turning them down that I'd automatically say yes without giving any thought as to whether it was something I wanted to do or even had time to do. I was more concerned with not hurting other people's feelings than I was with hurting myself.

It did not help that I was everyone's first call for their carpooling or babysitting needs, even though I have three small kids of my own and a husband who travels a lot. Whenever one of the kids' teachers needed a classroom volunteer or a field trip chaperone, there I was. If a friend needed help hanging pictures, off I went, hammer in hand. If a neighbor needed someone to watch their dog while they were away, I did that too.

I was a Daisy leader, a Sunday school substitute teacher, and the hostess of many holiday meals, birthday parties, and baby showers. I've been a bridesmaid four times, three of which I was pregnant or had just given birth. (Big bellies, leaky breasts, and fussy newborns do not go well with jewel-toned taffeta.) But I kept on saying yes.

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Then I hit rock bottom. I was beyond exhausted and beginning to feel bitter toward people. Once I realized this, I knew I needed help getting back, so I made an appointment with an amazing counselor who told me that life-changing advice. Once I gave myself permission to say no, my load got a lot lighter and so did my mood. By not doing things I'm resentful for, I have more time to do the things that bring me joy.

Here is my advice to you: The next time someone makes a request of you, ask yourself whether you will resent having to do whatever it is. If the answer is yes, don't be afraid to say simply that you are unavailable. Since this can be easier said than done, I like to use these three tactics:

1. Make a sandwich. No, not a real sandwich. Rather deliver your negative response between two positive ones to help soften the blow. For example, "I'm honored that you thought of me for this (positive). Unfortunately I am going to have to pass this time (negative). But I wish you the best of luck with your endeavor (positive)." It's simple, but it works!

2. Offer an alternative solution. When possible, suggest someone else who might be able to help. Or, if there's anything different that you would be able to do willingly (and happily), offer to do that instead.

3. Put yourself in their shoes. If you're worried that someone might be hurt or angry with you for turning them down, try imagining if the roles were reversed. If someone turned you down, would you be upset? If not, then they most likely won't be either.