A non-gamer hesitating on his first turn in a simple filler game with me recently made the following comment: I don't like not knowing what to play.
The very act of calculation against the unknown possibilities was not fun for him. I wanted to explain that decision-making was the definition of fun; I had to fight myself to listen to what he was actually saying: I don't find this fun. It was a difficult, but important, struggle. I think of decision making as the heart of a game and the heart of the fun. This is not the case for everyone.
Some people don't enjoy games, period. Some enjoy the company. Some like to watch what happens, and may even be excited about the game as it happens; they just don't want to guess. Let them pick a card or tell them to roll the dice. Give them a skill to perform or all the information they need for a quick calculation, but don't force them do math or memory or decide whether or not to buy something with a hidden value.
We need to listen to our gamers, just like we need to listen to our children or our parents when they tell us something. We can't just think that they're not seeing it the right way.