Question's for God.

[Angrboda]

A restful mind is good for some things and bad for others.  Rushing to embrace one or the other is irrational and probably harmful in the long run.

It is all relative yog.
By playing chess or do things that require a big mental effort you strain your mind.
If you instead use that mental strength to practice yoga meditation then a positive reward take place.

This is nothing but a bare assertion.

I looked further into the literature. In 1992, David Shapiro, a professor at UCLA Irvine, published an article about the effects of meditation retreats. After examining 27 people with different levels of meditation experience, he found 63 per cent of them had suffered at least one negative effect and seven per cent profoundly adverse effects.

The negative effects included anxiety, panic, depression, pain, confusion and disorientation. But perhaps only the least experienced felt them – and might several days of meditation not overwhelm those who were relatively new to the practice? The answer was no. When Shapiro divided the larger group into those with lesser and greater experience, there were no differences: all had an equal number of adverse experiences. And an earlier study had arrived at a similar, but even more surprising conclusion: those with more experience also had considerably more adverse effects than the beginners.

http://www.independent.co.uk/life-style/...68291.html