Why do we say we will do things and then fail to do them? We overcommit ourselves. We don’t like to disappoint people, so we tell them what we think they want to hear. We feel pressure in the moment and don’t stop to consider how much pressure we’ll feel later. We don’t think through how much time things will actually take — and we don’t leave enough slack time in our days to handle the (inevitable) emergencies and delays.

And, then we feel guilty about it. We waffle over what to do — and the indecision is draining. Finally, we cancel, and we undermine our confidence in ourselves. It reinforces our conviction that we can’t do it all — that we can’t control our schedule, or even our effort.

There are consequences, however. Keeping commitments is a sign of maturity. Employees who don’t finish assignments, for instance, or finish them late or poorly, or are themselves routinely late, miss meetings, and cancel appointments, are an imposition on other team members and a liability to their employers.

Because these bad habits are nearly ubiquitous, they inevitably hitch a ride with some of us as we climb the ladder into leadership roles, where the workplace dysfunction they generate is magnified. It’s difficult to hold your subordinates accountable when you don’t hold yourself accountable. It’s hard to trust others when we know we can’t be counted on. How do we inspire commitment in those we lead when it’s obvious to them that commitment is a negotiable principle for us? It’s impossible to be a good leader if we don’t govern ourselves.

If you really mean no when you say yes, then say no in the first place. We are all in the same boat — we have finite time and a seemingly infinite number of worthwhile things to do with it. Don’t know how to say no? Google “how to say no to a request” and then study up. Commit yourself to not agreeing to do things unless you’re going to follow through. Ask for time to think things over if you’re unsure.

Don’t overschedule yourself. If you’re truly overextended, you may require a transition period to weed some things out; after that, once you say yes to something, stick to the yes. If the commitment seemed like a good idea at the time, it still is — even if the value is found not in the activity itself but in being trustworthy and following through.