Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth.

Every account of the world arrives already shaped by whoever is delivering it, including the account your own eyes provide. That is not a reason to believe nothing, which would be its own kind of foolishness. It is a reason to hold your certainty a little more loosely, particularly the certainty that feels most obvious, since obviousness is exactly what an unexamined viewpoint feels like from inside.

In your next disagreement, try to state the other position well enough that the other person would recognise it. Notice whether you can. If you cannot, you were arguing with a version you built rather than with them.