Don't underestimate

Ignorant is who finds himself smarter than others. One should never underestimate people. Many times people thinks that silence means that the person don't get how fake the person is being with her. But that's not like this. Many times I know that someone is fake with me but even so I control me and keep it for me. Normally I'll always say what I think, etc. but sometimes I keep it for me. Sometimes I think that there is a better moment to say what we think than the moment self. Sometimes the best is to let that person think we don't know anything. Many times people think that because we are friendly persons that we are inocent and we will not see how fake they are, but that's wrong. Sometimes people make a wrong prognostic of persons. I'm not inocent just because I'm friendly, because I can be playing her game without she knows it. I can just being friendly with that person to make her think that she got me in her lies. 
That's the problem of people who thinks to know everything or thinks to know enough a person. That's a big mistake, because there is a risk to fall into it's own trap. Because you think that the person don't know anything, in reality you're the one who don't knows...you don't know that the person knows. 
So I give you guys an advice.
Never underestimate anyone because if you do you will be the ass in the history.
Never underestimate, the presentiment of the person, person's strength, the will of the person, the intelligence of the person, etc. Because she can surprise you.