"So for you either a show is one of the best shows you've ever seen or a horrible abomination?"
I think we can dial back the rhetoric a little and perhaps say that, for some people (many?) shows are either just "good" or "bad." Some audiences have a lot more patience with old tropes, clichés, and hackwork than others. For some, a charming performer or a good loud voice make up for uninspired writing. And it doesn't always have anything to do with how much one has seen - I know someone who has been going to the theatre for 40-some years, and still says he likes every Broadway show he ever sees (he's less enthusiastic about Off-Broadway, for some reason).
Personally, I'm rather impatient with seeing the same old schtick, the same old plot devices, the same old dance moves, the same old obtuse lyrics, the same old foursquare music.
But it seems that every season, there's at least one musical - and maybe more plays - that stand out as being a bit brighter, wittier, more thoughtful, more special than the rest of the herd. Shows that aim to be more than just another clone from the profit-seeking mold. I love those shows - Meteor Shower, The Band's Visit, A Doll's House Part II, Fun Home, A Gentleman's Guide, Matilda, Hand To God, etc.
Pretty Woman (to me) was just another dire attempt to wring more cash from a famous movie (and it just may succeed).