Neither your thoughts nor mine are to be trusted if they come from the ego-mind.

Why not trust them?

Much of your thoughts/self-talk is made up of old limiting suggestions you received as a child. Sure well meaning (and mean) parents, teachers, peers etc gave you these ideas and often they were not true yet they still run your life today.
Your mind can rationalize just about anything so it needs to be questioned. It can rationalize absurd ideas like going to war, the death penalty, having a drink when you’re an alcoholic, and the idea of someone sitting on a throne up in heaven, and so much more.
Your thoughts are made up of words not reality. Words only have the meaning you give them. Let’s use chocolate as an example. Chocolate has gone from being bad for you to good for you. Same chocolate but beliefs have changed. All thoughts need to be seen beyond the words. Underneath every thought there should be a question about is this real or not.
People with strong beliefs systems actually think they are right and others are wrong. Beliefs are just thoughts people think over and over again. Is God a member of only one religion as many religions claim? Would he actually help your sports team win over another? The answers are obvious no. All beliefs must be questioned.
If you follow politics you may have noticed that there is very little difference between political parties since both Democrats and Republicans are hugely influenced by money interests. The media plays up the supposed party differences and plays down the group think of politicians who all seem to be owned by corporate interests. Many people actually think one party is better than the other, a closer look might inform you that there is little difference once they get into power. Thoughts are just thoughts and not more real than other thoughts. Liberal and conservative are just words that have become very charged but underneath there is little difference in actions they take in Washington D.C.
There are many more examples of the mind wandering about with thoughts that are not real. Thoughts of not deserving, thoughts of self-doubt, thoughts of specialness or not, thoughts of good and bad, thoughts of needing the approval of others, thoughts of expectations of others, thoughts of judging self and others, thoughts from the inner critic, and on and on.

Question, question, question every thought all the time.

Can thoughts ever be trusted? Yes there is a higher knowing within us that goes beyond the yakity-yak of the ego-mind. This higher knowing can be found in the quiet of the moment and nowhere else. Meditation and mindfulness are recognized practices worldwide that nurture a more expanded consciousness and a higher knowing. There are people out there through their writings and presentations who are spreading a higher consciousness. You can tell who they are because when you sit and listen with an open mind and heart, you can feel the truth of their ideas.

The best way to treat you mind is to observe it objectively and note what thoughts and feelings feel right and uplift you and what thoughts and feelings make you feel uneasy and contracted.

Move towards ideas that expand you and away from ones that cause you to closed down in some way and keep questioning your way to a deeper truth.