Our assumptions can cause us to miss out on a lot.

If you assume that this customer won't buy, you won't put in the effort to engage them. You just missed out on a sale.

If you assume you know what your friend means when they say "I'm doing good" when you ask how their day is going, you'll miss out on a chance to help if they're going through a hard time or a chance to celebrate if they had a win.

If you assume that someone else will take care of it (whatever that is), there's a chance it won't get taken care of, and everyone misses out.

Rather than assuming, ask a simple question like "What do you mean by that?" or "Great! What's going good?" or "Is anyone taking care of this?"