Though thinking is beneficial and helps in long term there is still a need for balance. Thinking and assuming too much on small issues results in things becoming big and scary in your head, a stray remark or a innocuous comment or decision can become a virtual hell and cause negative attitude if overanalyzed.

Focus on the issue rather than slipping into the assumption and fantasizing mode.

Be rooted to reality and in present rather than imagine things

Use thinking as a tool rather than letting thoughts control you.