Children need to know the difference between pretend and real. Adults can help them learn that difference.
For young children:
Play make-believe with them. Tell them you are having fun pretending, and agree to pretend for a set amount of time. Then, say you are done pretending when the time is up and point out what is different when you stop pretending. You might put away the dress-up clothes and say you are going to wear your everyday clothes now. You can say the table is now a real table, not a fort. You might put away the play dishes and get out real dishes with real food for lunch.
For older children:
Play “What-If” (https://wp.me/p2MePX-28G). Make up a “what-if” situation and see where it goes. For example, what if you stopped loading the dishes in the dishwasher every night? If your child answers with a fantasy, like a fairy would come and clean the dishes, remind him to give “real” responses and ask for another idea. Anytime he gives a real idea, like we would run out of dishes for the next meal, compliment him on figuring out something that could really happen, without saying whether you agree with it.