Impulse Control

I have a hard time controlling impulses a lot. Like last night a friend offered me some cocaine and instead of saying no(i dont even like the drug) i said sure cause hey its free. Or if i see something on ebay really cheap(500 cheap things become expensive) i have a hard time not justifying it in my head. I realize at the time that its wrong so its not that,, i just end up talking myself into the stupid act or i do it without thinking it thru. I could probably make a list the length of a highway if i bothered to think of all the times ive just had an impulsive thought and went with it. If i know its wrong and i know its an act or behavior i dont want to do then whats the problem? Should be an easy decision. Not so apparently for me. Im not even sure what im asking here, assuming the following of impulses is a symptom of mental illness and not just stupidity what are things i can do to make sure i make the right decisions?

I been learning about boundaries and self-definition a little lately. It sounds like you might lack boundaries. Like if someone says You want to do coke? you hear Do coke
You want to buy this? you hear Buy this
Do you trust me? you hear Trust me- and you act on the abreviated message- so first put the message back into a question and then ask yourself the question and wait for the answer.
Thats what I'm trying to teach myself to establish some boundaries for myself right now. I hope this is some sort of help.

interesting-
thanx-

I'm not so good in the old impulse control department either. Do first think later seems to be my motto sometimes. Often I can see 'I am going to regret this later' flashing through my brain - but it just isn't as loud as the 'screw it - lets do it' voice. Hmm. Delay.

Mindfulness meditation is good for learning impulse control (in theory).
You feel an itch and you just feel that itch and resist the impulse to scratch.
You feel an impulse and count to ten
Take deep breaths
Then hopefully at the end of the ten you can resist the urge.
Ah.
Theory theory theory...
Let me know if you find anything that works

Havent really found anything that works but i think the realizing that there is a problem helps somewhat. I still fail quite a bit with the "screw it, lets do it" thing goin on in my head too.

I think like both of you said slowing down and thinking it thru rationally(haha not my strong suit) does and can help. Anyway its been a little bit of time since i did anything to rash so hopefully im more under control. Thanks kathy and alexandra.