As I've said before:
Remember that the problem is not only confined to the effects of the alcohol itself (intoxication, lack of judgment etc) but also spreads itself across the rest of life with craving for the stuff when sober, irritability when sober etc
LOC if you feel 'good' for 'having a couple' after a stressful day then you are on the slippery slope.
Bet you when that when the stress was mounting you already looked forward to those few glassed of malt you 'promised' yourself.