There are ways of reducing unnecessary emotions; the ways that work, however, don’t depend on pretending.

Not the way you meant, certainly, but pretending is still useful in other ways. A lot of desensitization techniques involve imagining the stressful situation. And some mental techniques which are supposedly helpful involve visualizing the actions that are going to be taken; this seems to be used in the context of athletic performance.

I've found that if I imagine doing something too clearly, my emotions react as though I've done it already. If it's virtuous-but-unpleasant, I usually end up not doing it for that reason.