Hollywood stars face accusations of pretentiousness whenever they employ method acting, and you can sort of understand why. While it's commendable that Christian Bale dropped a third of his body weight for The Machinist, it's hard to see the benefit of stalking a woman for real in preparation for your role as a serial killer (yes, Jamie Dornan did once admit to this).
In wrestling, however, things are arguably a little different. For one thing, it's live. There are no do-overs, and therefore no time to practice playing your character, at least not in front of a live audience. The only way you can really test-drive a new gimmick is to assume it in everyday life, cutting near-the-knuckle promos on your local shopkeeper, screaming about how much you hate America while in line at the bank.
OK, neither of those are particularly sensible ideas, but you get the point. Over the years, several wrestlers have gone to extreme lengths in order to prepare for their upcoming role - be it physically transforming their body, acquiring a completely new skill, or simply taking the gimmick out for a spin in public.