Perception vs Delusion?

You know when you've known some people well after a long time, you begin to be able to guess what they'll say about a certain topic or how they'll react to a certain problem or situation? You can just imagine having a conversation about that specific topic or problem with those people and carry on the imaginary conversation in your mind.

How far can we trust our perception?

I've been burned a few times when I perceived something based on my observation. I confronted some people about what I thought as A, yet I was stunned when I found out their sides of the story. My perception changed COMPLETELY!

If something ticks us, surely there's something inside us that makes it that way, don't you think? It's quite hard to get rid of a certain perception once it's mapped out in your brain.

Don't you just hate it when someone says something to you and at first you think of nothing much, but then your brain starts processing it (perceiving it differently?). I've had my shares of condemning that little voice within me that nudges me like that. For example: If someone compliments you, at first you feel happy, but then a second later you start wondering if the person has an ulterior motive in doing so. Then I start beating myself up for managing to think of such an ugly thing. GGGRRRRRRRRRRR!!!

I know that that little voice is there for a reason, but if that little voice comes out as a reaction to something said by someone that's close to us, it makes all the difference in the world. It's normal if people are suspicious about strangers, but it's killing me if I begin to suspect the motives of those people close to me (especially those whom I know have no intention of hurting me). And I begin to wonder whether it's a real, true perception or if it's just a delusion. Or whether it's due to that something inside me that is triggered by what they say.

All in all, I've been asking for discernment. I don't wish to let go of my perception, but I wanna know which is which and I wanna be able to get rid of the false perceptions.