I have always considered Jupiter's marginally isolated status to present a low-grade vulnerability in my chart. True, it's dignified in Sagittarius, its sign of rulership, and is nominally in the 1st House. However, it's not posited in the ascending sign (Scorpio) and some authors would consider it "stranded" in that house. Traditionally it would be considered a 2nd House placement since it sits less than three degrees above the 2nd House cusp. Both considerations are relevant here.
Jupiter is a bit of a maverick in my chart since it is isolated from the rest of the dispositor tree: at least in contemporary terms, it disposits nothing and in turn is disposited by nothing (but more on that in a bit).
Taken as a 1st House Sagittarian Jupiter, it imparts a vulnerability to "foot-in-mouth disease." I can sometimes open my mouth before engaging my brain. There is absolutely no intention to hurt, and I'm invariably dismayed by perceptions to the contrary. But it just . . . sort of . . . comes out . . . !
Taken as a 2nd House Jupiter, it bestows an urge to spend (especially on things that expand my mental horizons), no matter how much scolding I get from my 2nd House Moon in Capricorn (oh, and my wife!). Jupiter is trine my 9th House Saturn, which disposits the Moon, so I can always come up with a rational excuse to cheerfully override that cautious lunar prudence. And the quintile between Jupiter and Neptune in Libra on the 11th House cusp lends a fascination with all manner of artfully presented esoterica to blow my money on (think "occult" books and tarot decks). The opposition to Uranus in Gemini is also not conducive to austerity where mental stimulation is at issue.
Lately I've been calling Jupiter the "Phantom Overlord" of my chart, ever since I discovered that it's in mutual reception "by face" with Saturn, in addition to their affinity by trine in the Fire triplicity. Since Saturn is part of the "committee" (Kevin Burk's term) that presides over the dispositor tree (Saturn-Sun-Moon, with the last two rolling up everything else except Jupiter), and Saturn in its traditional detriment is subordinate to Jupiter in its sign of rulership, a case can be made that Jupiter has an "underground pipeline" via Saturn to the head of the class. Since Jupiter is in kind of a "gunslinger" posture in it's relatively unfettered, oriental placement, I sometimes run with my instincts instead of pondering the consequences beforehand. And generally I don't embarrass myself.