This one I can define in best way as I am going through one smile emoticon .

So, under Jupiter Mahadasha, Jupiter will give the results of the house it is sitting in, houses where Sagittarius and Pisces are placed as Jupiter rules both these signs, houses where planets are placed in Jupiter ruled Nakshatras (Punarvasu, Visakha, Poorvabhadra) and of the house where Lord of the Nakshatra is placed in which Jupiter is sitting.

Now, apart from all these houses, Jupiter will give results of things which it represents like religion, hope, faith in God, philosophy, spirituality, charity, reading of spiritual texts, occult knowledge etc.

So basically, no matter where Jupiter is placed in horoscope and it is in which sign, your standard of life will be improved. As it is the most benefic planet, even in its worst position, it still improves the status of the person. Receiving wealth is always on the cards during Jupiter Mahadasha as Jupiter is significator of wealth, but the main thing which will be coming your way is Spirituality. In Jupiter Mahadasha, just be ready for overdose of Spirituality and it will never be a forced one. You will be inclined to follow the spiritual path during Jupiter Mahadasha, if Jupiter becomes Atma Karaka or Amatya Karaka, things go up to the highest level of Spirituality. If Jupiter is in Cancer, Sagittarius or Pisces, this time period can make this person almost a Saint or Monk, taking the spiritual life as his overall life purpose. If Jupiter is in these signs, the person always thinks for himself as a fortunate person and he is always looking for the higher purpose of life. He is always hopeful for future no matter how much money he has in his pocket.