Emotions
developed as a reaction are stored in the mind permanently.
These reactions are accumulated in the mind and create
mental strain. This is more dangerous as it becomes
a part of mind. Removing this strain is extremely
difficult. There are few advance techniques, which
help reduce this type of strain. Relaxation is one
of those techniques.
Thinking process of the mind also creates strain on
the mind and to reduce this strain, we have to reduce
the thinking process itself.

Doing
something is Strain.

Doing
nothing is Relaxation.

Actually
doing something to learn the technique of "Doing
Nothing" is Relaxation technique.