Things That Are Difficult to Say When You're Drunk:
Indubitably
Innovative
Preliminary
Proliferation
Cinnamon

Things That Are Very Difficult to Say When You're Drunk:
Specificity
British Constitution
Passive-aggressive disorder
Loquacious transubstantiate

Things That Are Downright Impossible to Say When You're Drunk:
Thanks, but I don't want to have sex.
Nope, no more booze for me.
Sorry, but you're not really my type.
Good evening officer, isn't it lovely out tonight?
Oh, I just couldn't. No one wants to hear me sing.

Think youve hit the nail on the head there!!!!