Personally, I don’t think not trusting people counts as a bad habit . I like to think it has to do with individual preferences. Some people don’t like to open up to others and and that’s totally fine.
Assumption on the other had can lead to a lot of problems , it’s better to ask and get the right answer than to assume and not even know the truth.
I assume alot and yea it also make me act fasT When it comes to cuttiNG people off, and seems you are right, Sometimes Things maY not be as We aSsUMED IT to be