When we spontaneously emit an emotion toward something imagined on a blank stage, that's crazy - and the audience loves it.  Society's path to "maturity" often overlaps with a push to subdue your emotions; the upside is that people like watching other people share their emotions on stage - it's a cathartic surprise.  A scripted actor’s whole job is to make an audience believe that the emotional reaction they’re rehearsed is real in-the-moment. In improvisation, we have a leg up; we are all experiencing what’s happening for the first time.  And as improvisers we don't have to understand our motivation to emote; we just have to emote - feel!

If you don't have feelings, get off the stage.  An improviser without access to their emotions has to be a very "clever" improviser.  Relying on cleverness alone works for very few people, let alone improvisers.  Not engaging your emotions is improvising without one of the core elements of improvisation that can evoke a response from the audience beyond the capabilities of any other performance medium.