The real cost of “weak” promises (weak = promises we don’t intend to keep) is that we take our word less seriously, one weak promise at a time.
When viewed in the short term, this doesn’t necessary hurt us much. But, over time, this compounds into us completely losing trust in our own word. The danger lies in the compounding, of course.
Don’t say yes when you want to say a no.
If it isn’t a HELL YEAH, it probably is a no.
If you find yourself faced with a promise you regretted making, keep it anyway.
If you do decide to break it, call it out loudly instead of slinking away into the darkness. You should feel the pain when you don’t keep commitment.
We learn to trust ourselves by keeping one promise at a time. And, if you can’t trust yourself, why should anyone else?