Breaking a Serious Promise

I avoid making serious promises because it never ends well. If I make a promise, then cannot keep it, I feel horrible. So I just do not make the promises to people. I either do something or I do not, I am really a last second kind of person - doing as I go. Therefore I can never really guarentee something. I remember years ago I made a lot of promises and it just ended up creating a lot of stress for me and everyone else. The only thing I ever really promise anymore is doing chores for my dad, and that never ends well because I am either busy, at work, or forget so it usually just ends with him mad and me in trouble.