Munna Bhai gave yet another medium to express gratitude - Jaadu Ki Jhappi. Suddenly hugging someone just like that was cool.
This Jaadu Ki Jhappi was meant to express gratitude, to help someone raise their spirits, give someone respect, shower affection and what not.
One simple gesture was transformed into a nationwide infatuation.
Obviously the second Munna Bhai gave something much much bigger. Gandhigiri. Suddenly Gandhigiri was cool and was admired.