Vairagya is very important for the mind to get withdrawn from this illusory world. As long as the mind thinks this world as totally real and it imagines that this world can give me all the happiness and peace that I am looking for, it would not like to give up its imaginations and come back towards the Self. That is why vairagya is very much required. That is why since ancient times it is always taught that as Adi Shankaracharya puts it, "Jagan mithya, Brahma satyam", meaning, this world is unreal like a long dream experience. Just like during the dreaming you are dreaming that is real, but all the things that you are dreaming are unreal. But as long as you dream you cannot make out that you are dreaming at all. It appears so solid; sometimes the picture in the dream may be very solid that you are unable to forget for a long time. Sometimes the picture may be vague and blurred; you would have forgotten by the time you get up.
So that is the effect of this illusory world when it affects the mind. So it is essential that the mind needs to understand that all this world is unreal: "This is transitory. This is not going to give me a permanent happiness or peace". Like I used to think as a child, "If at all we have the happiness, we must have it for all the 24 hours and 12 months".