I know my limit and stay within (I am not into getting so drunk that I feel sick).
Low tolerance to alchohol works both ways.. On one hand, you can pretty much forfeit any competition involving alchohol (pub golf, bets, dares etc.).
On the other hand.. I can probably have a night out with a tenner (unless I buy rounds).
I know some people who'll need £40-£50 for the same effect