Justin Parrot aka Abu Amina Elias wrote on his FB page

"We’ve heard the Prophet ﷺ tell us to speak good words or be silent, but have you considered that it refers to our inward statements as well? Bad thoughts create bad feelings, which lead to bad behaviors. When we habitually dwell on negative things in life, our worries, our doubts, our anger, and our worst-case scenarios, we get sucked into a downward spiral of depression. The way out is to train our inner dialogue to dismiss these thoughts, these empty frivolous fears that are no more real than a monster hiding under your bed, and replace them with prayers, with faith and optimism, with a look on the bright side. Think about your blessings, everything that is going right in your life, everything beautiful and peaceful. The God who parted the red sea, who brings the dead back to life, who performs miracles has the power to help us through any trouble. Say it to yourself. And if you have nothing good to think, then don’t think anything at all."

A comment in response (by me)
"But that will be inhibiting thoughts... We cant not think of bad things... i think that as long as you dont follow up that thought with any action, that it is fine... but it is my opinion..."

Justin Parrot aka Abu Amina Elias responded
"I’m talking about negative inner-statements like thinking pessimistically, nurturing anger, or saying bad things in your mind about yourself and others. Thinking itself is certainly a good thing when it is constructive and leads to good behavior and outcomes."

Another comment from another person who agrees with him
"Excellent point you made here Justin. I have been known to think of the worse case scenarios and all it does is hurt me. Thinking positive and doing hard work and leaving it to Allah at the end of the day makes for a healthy mind and positive emotions. Unnecessary stress is very bad for the body."