What’s the most powerful key on your keyboard, the most powerful character in the English language? Without question, it’s the question mark.
Let’s compare the question mark to the period. A period invites silence, because you’ve told the audience the conversation is over. Nothing more is needed. Nothing more to say.
A question mark, however, invites them–encourages them, even–to be part of the conversation. It signals that the conversation is not over, and that the rest of the conversation, in fact, is dependent upon them.
Are you asking enough questions? Are you taking full advantage of the most powerful key on your keyboard?