You're discounting the case where precisely because it fits the narrative, it is effective.

Getting coffee and building the narrative of "I'm a Hard Worker who will now do his Hard Work with Focus and Determination, look at me getting ready with coffee" is priming yourself for that hard work, the narrative is part of your motivational structure and embellishes your Focus and Determination.

Being too aware of "it's only plain old me, whether in a uniform, or in an office, or at Starbucks" is needlessly sabotaging an often effective placebo-like effect that relies on your internal narrative.

Epistemologically useful, possibly, but contraindicated as an instrumentally useful habit.