I prefer the slimmed down interact/examine scheme that AFRLme mentioned. While lots of verbs allow for a more specific answer to a puzzle, it usually just end up causing confusion.
It puts the player in a position where they not only need to figure out what they should do, but what action is its closest representation (according to the designer!).
Do I need to “Open” a letter to read it, or perhaps “Look at”, or worse “Use”?
That type of pedantry really pulls me out of the story. Obviously, opening and reading a letter - one of the most menial tasks imaginable - should really just be a matter of one click. You don't forget how to read a letter, so there should be absolutely no mystery to doing that.
However, if you what you are aiming for is a straight up comedic game, I have to admit it can be very funny trying out different verbs. Just be aware it can be difficult to stay immersed in the story while doing so.
A quick note on complexity. I don't think a game should be difficult in terms of the interface, it should be difficult within the context of the story. That is, if the player faces a complex situation, the character should also be facing one. The letter-example above illustrates a mismatch. That situation is only complex for the player, not to the character.
If you want to make your game hard. Try to think of situations for the character to face that are difficult to figure out from first impression. Because difficulty should come from figuring out the right solution, not how to execute that solution.