If you are around people that drink and you are not drinking and do not want drink, you have to very carefully watch what you think/put into your subconscious because it is likely that you will develop the subconscious desire to drink at some point in the future. These desires are called samskaras in yoga. Subconscious desires. If you do not monitor it, you may in the future be provided the opportunity to drink and because you are unaware of a lurking subconscious desire you put in your brain earier (or many of them) you will have to suppress the desire. You can only do this for so long. The way to not supress desires (become subject to karma) is to understand your thoughts. Repressions can not stand the light of understanding. Once understood, they evaporate. If you do not put the wrong thoughts in your mind to start with, they will not crop up in the first place in the future to begin with.
Thought watching is a mystical activity I learned from Satguru Subramunia. It is only spiritual people that can ultimately be successful at this because the ego hides many things from your conscious mind that are not pleasant to you. Only from ruthless fearless inner scrutiny and relentless persistence of this activity do these skeletons in your closet emerge. For such inner strength normally yoga or some other means is required. It is also by this means (and mantra and samadhi) that past lives can be recalled. By thought watching I mean at sudden unexpected intervals - interrupting yourself and asking 'what am I doing?' Then track backward in your thinking to discover the desire that led you to be doing what it is that you are doing (in yoga this would be to discover what attachments you have to the material world that hold you bound to the wheel of karma/birth and death from desire). Then ask - 'What was I thinking?' Then track backward to discover the origin of this like of thinking. It is a very telling means of discovering how you can be led to think and believe very bizarre things by ego.