Why break the habits of a lifetime?
We might say that usually when someone says they will change by stopping doing something they shouldn't. But it's said so tongue in cheek that it is obvious we don't believe they will change. So it's not the most encouraging thing to say to someone who wants to change their habits since it immediately dents any hope they might have of changing.
Predictable patterns of behaviour are helpful sometimes in being able to respond or plan for the future. and generally repetitive behaviour, while sometimes annoying, at least gives some certainty about the future.