The way we think, we are such. We must control our thoughts. Prayer and constant remembrance of Godhead helps us to control our mind. They help us to our mind, which is still running, and set it calm, in silence. Thanks to silence thoughts disappear.
If you think negative thought and let it all around you, everything becomes negative. There will be nothing positive. But if you keep this positive idea within, through prayer and through inner silence it is dissolved. But no, we like to express our thoughts. You will not say "No, do not do it," but first you manage, then you can comment.