Most of the times our view is limited.
We see the world through the lenses of our own experiences, whereabouts, and expectations, yet we seem to like taking our limited experience and generalizing it.
Each time you find yourself doing that take a step back. Try to look at the situation from the eyes of the other person.
At times you might still think that your point of view is solid, other times it might change how you think about a problem.
Here I'm going to make just one example to show it in action since it can be applied to all areas of life the examples you can come up with are basically infinite.
It's easy to judge and bash previous developers. Their code sucks. I can't believe they did it like that. Why would they?
If you haven't been in the original development team, you have no idea under which constraints the app was designed and developed. There might have been time constraints, resource constraints, management problems and many other issues that could have caused the code to be terrible, but that's not the developers' fault. Jumping at conclusions and blaming the developers is shortsighted and often wrong.
After reading that you might think to blame the manager, the owner or maybe the client, but if you don't know what really happened you shouldn't blame them either. The lesson is not to shift the blame onto someone else, but to realize what we don't know.