Relapses for me have been triggered by cognitive distortions or rationalizations that allowed me to fool myself into thinking it was okay to drink again, or go ahead and have "just one," despite repeated past failures to control drinking, repeated vows not to drink, and knowledge of the likely unpleasant consequences. Some examples:
"I have been sober for many months now without any difficulties, so I have demonstrated that I can handle it."
"I just got through a major stressful time and got a lot accomplished, so even though I should be staying away, in this case I deserve to have one drink."
"I don't seem to need alcohol anymore, so I am curious to know what it would feel like if I tried one drink."
"This is a really fun event I'm at, so it would just be a real shame not to have one drink while I'm here."
"I've been doing great with sobriety, but I just want to take a little vacation from it. I just want to go to 'that place' one more time to get a little insulation from the world. Everyone deserves that once in a while. I will be back on the wagon tomorrow."
"Since I'm not the kind of person who really HAS to drink, why not give it another try?"
"To heck with everyone else, I'm just going to do what I want."