Mercury Square Or Opposite Pluto

This aspect adds deep insight, mental focus, and observation that tends toward the negative or paranoia. Your expression  is subjective and  bias based on personal experiences that led the individual to believe that most people are not to be trusted, which can lead to a very suspicious and assuming the worst, mind.
 If you have this aspect you tend toward pessimistic thinking, and that people are not to be trusted. Although this mindset may very well be justified the continuation of these thought patterns are to your detriment and will affect your life in harmful ways, with regards to relationships with others.
In relationships you tend toward the extreme, you can be overly suspicious, jealous, demanding and defensive. It would serve you best to understand, that a change in thinking is necessary. 

While young the native felt as if they could not trust their environment. They may have had to endure an overly stimulated, aggressive early childhood, where they felt undercurrents of manipulation or passive aggressive behavior, and in some cases were witnesses or victims of verbal abuse. The child may have felt manipulated or  dominated and have issues with trust as the result.
People do not like to be pushed, blackmailed, or threatened or constantly doubted. This aspect can make the person feel the need to dominate conversations with others, and although it may work initially somewhere along the line, people will not associate with you anymore because of this.
 Learning to speak with composure, tact and to think things through before responding would be wise. Compulsive reactions often lead to regrets or foot in mouth syndrome.
Anger needs to be controlled, being explosive only makes one look out of control. You don't need to blow things up beyond repair, and some things just don't need to be won or said. It's important to choose your words wisely and to learn to express yourself without blowing a fuse. You will end up burning many bridges in your path.
The negative slant  is serving to undermine your happiness. Learning to let go of the and let be and to not take everything so personally will allow you the inner peace of mind that your body truly needs.
Finding a positive outlet for your focused and powerful mind would be ideal, meditation, research, analysis or investigations, just not strictly focused on finding the negative in your partners, or people in general. Yes. bad people do exist, the key is to steer clear of them or let go of them do not to hold on to them, or to try to change them.
This aspect creates a laser beam mind and once focused the native can not let go,  and if they are unable to get immediate answers they  tend to force the result, often with threats or demands. This, however, pushes others away and alienates yourself.
Give your mind a break, don't focus on the negative, instead turn your thinking to the positive, the focus power of your mind can do great things, but too much time is wasted on worry, fear, and obsessing about every detail, learn to let go and let be, it's very liberating and you will find much happiness in it.