A craving so powerful it was beyond my ability to control always kicked in after the first drink. It was the result of the presence of alcohol in my system. Typically I could not stop until I was too sick to continue, after about four days. Then it would take about three days for the alcohol to get out of my system. After that the craving could not happen so in theory I should be able to stay stopped.
This craving is apparently the result of the way an alcoholic liver metabolises alcohol and does not occur in ordinary drinkers.
Thoughts of drinking are a different thing altogether. If a concious thought occurs and it is countered by sane logical thought (play the tape etc) or action, call someone and talk it through, it shows that there is a defence against the first drink, and things ought to be ok.
The obsession of the mind is a different ball game. Insidious, subtle and cunning it quietly puts forward the thought "that this time it will be ok". Little casual harmless thoughts, "I'll be able to have one" "Just one I've earned it", "My friend offered me a drink, it would be rude not to accept" and so on. The very real reasons for not taking the fatal first drink do not come to mind, or if they do they are easily dismissed.
When the mind is in this state, the insanity of the first drink has returned. It doesn't occur to call or play the tape through etc because it has already been decided that "one won't hurt". It is interesting to read "I am back posts". I don't think I have seen a single one describing a huge battle with cravings before picking up the first drink. Usually there is some trivial excuse "my car broke down", or "my dog got sick". Sometimes the excuse not trivial, but it still does not stack up as a reason to drink.
Quite often the poster will say they really don't know why they got started again. That was my experience.