When can I "what if?"

Native speaker’s answer
Rebecca
You can use "what if" at the beginning of a question to propose a hypothetical situation. For example, when you're not sure what the outcome of something will be, if you think about different alternatives in the past, or to consider different possibilities. Ex: What if we hadn't come on vacation? We'd probably be bored at home. Ex: What if she wants the red dress instead of the yellow one? Ex: What if a customer complains? What do we do then?