First of all, one should understand no planet is good or bad; no planet gives automated/predefined results. So, one should try to understand the reasons behind any planetary position allotted in the original horoscope. You get all planetary positions as a result of your past life deeds. In my opinion, one should care more about negative planets and try to understand how to mitigate their harmful impact of the same in the present life. This is the basic Theory of Karma. The same rule applies to Jupiter as well. If you have mishandled/abused some particular traits/significations of Jupiter in your previous life/s, you are bound to get a bad Jupiter in your birth chart/horoscope. Now understand the role of Jupiter.