I'm not convinced it is a bad thing. Why would it be a problem for "avoid mood changing substances" to become a habit, calcified and very difficult to uproot and change?
So it's back to the concept of a recipe where the ingredients change, but the recipe sort of stays intact. Change too many ingredients and we have an entirely different dish. I like this analogy because it's less formal and more forgiving. Just make sure to stick to it in an informal manner and not abuse the leniency provided, and you shall be fine. Technically every substance is mood altering (sugar for example), but there are some that have a marked increase on judgement and mood that it is safe to treat them as suspect. When I refer to "recipe" I mean a loose guide to run with in times of crisis.