If you were suffering from clinical anxiety as PTSD and ACE patients do then you might find cannabis to be the one thing that makes your mind clear of distracting fear and flashbacks. Assuming that all people and minds and drugs interact in the same way is a huge mistake.

Not in the context of drugs, but I find I am at my best when my mind is calm. I find it hard to be happy or productive when my mind is racing.

A clear mind and top speed thinking are things that contradict one another. The faster you think, the harder it is to concentrate on one thing.

As a person with Attention Deficit Disorder, I can attest. I am prescribed amphetamines to slow me down, not speed me up!