Science has a habit of asking stupid questions. Stupid, that is, by the standards of common sense. But time and time again we have found that common sense is a poor guide to what really goes on in the world.
So if your response to the question “Why does time always go forwards, not backwards?” is that this is a daft thing to ask, just be patient.
Surely we can just say that the future does not affect the past because (duh!) it has not happened yet? Not really, for the question of where time’s arrow comes from is more subtle and complicated than it seems.
What’s more, that statement might not even be true. Some scientists and philosophers think the future might indeed affect the past – although we would only find out when the future arrives. And it may be able to due to an emergent property of quantum mechanics.