This is not a joke. If you’re giving people direction, just give people direction. Tell them, “Press Enter”. Then if they press something else, you can still start the program anyway.

When you ask people to make a decision in something they’re unfamiliar with, all our evolutionary instincts to avoid making decisions before we fully understand a situation kick in. We get uncomfortable and that discomfort translates into uncertainty. We eventually press a key and move on, but you’ve already cost yourself a bit of satisfaction in the user experience.