Never Assume You Know People Completely
Lots of people make this terrible mistake, when they feel so connected with another person. They let their guard down, and open themselves up to these people; and in some cases they end up completely destroyed and broken by these same people.
This truth is that most people aren't what they seem like on the outside. This means that you must make efforts to observe people's behaviors to see patterns. And even when you notice a pattern, do not assume that they can't change that pattern.
As a businessperson, if you're so quick to trusting people and assuming that you know them completely - then you're risking the safety of your business. Because in real life, there are wolves in sheep clothing's - and they just need you to open your heart and world to them.
While you cannot live a life without trusting one or two people, you must make sure that you don't trust any human being completely. The fact is that many people cannot even trust their own self 100%, so it's irrational to put 100% trust in another person.
This is not to say that there aren't good people and trust worthy people - of course there are, but there's no sure way of knowing; hence, you always need to protect yourself when dealing with people in business and in your personal life. Expect the best from people, but keep your eyes open for anything unexpected from them.