what are the costs for going back on your word

[sakenagi]

if i say im gonna do something (let's say lose 3 pounds), and not follow through with it in the future. what does that say about me and who I am.

let's ante up. If I say that i'm going to give to charity this amount and even tell them I willl but back out on it. What does it say about me and who I am.

Does the first statement have the same effect as the 2nd one?

What's your opinion on saying something and then backing out on it. And have you ever done it before?

Do you value your words, or do you throw them away? I'm asking you, as the reader.