The adventurous Sagittarius has one flaw in their armor, and that is that being with others depresses them. For a zodiac sign that is known for tackling being alone the best out of the whole twelve signs, they also worry the most about being alone for too long!
Being without social contact of any kind, even when it is voluntary, may not be a problem for them at first. But after a long time, they realize just how lonely they are and how depressed that makes them. The bright side of this is that for such an adventurous zodiac sign, they soon get out of their rut and find joy again!
There are always new people to meet and new places to explore, and they get back to this rapidly!