Nonchalance. Watch for this. It is not unfriendliness or even arrogance, though the latter may also be present. Sagittarians love people, but they are not the subtlest of their sort or the ones best at picking up on moods and nuances. This is partly because the Sag doesn't draw a sharp line between people and ideas; sometimes they mix them together, and treat them kind of alike. A bright, buzzing, distracted disposition, if Sagittarius is strong. Two related qualities, sometimes immediately detecable beaming out from a persons very persona, are fanatism and "nerdiness". These are quite compatible with sagittarius.
Look for enthusiasm. Even a cool, controlled Sagittarius-type has that naively bubbling enthusiasm hovering just below the surface, ready to boil over at anytime. It is important to define a quite different Sag-type. This one is quite shy, not the first to get noticed, normally very intellectual, and profoundly critical, cynical and sarcastic. While it actually shares the qualities of the former type, this one has learned to re-direct them inwardly. Even this seemingly detached type has the warmth and idealism of the more obvious type. There is a certain openness about the face of a marked Sagittarius, an inviting quality and what might seem like lots of skin "surface". Some jokingly claim Sagittarians look like horses, but this shouldn't be taken the wrong way. There is indeed a noble, shapely quality to the Sag, having fine, generous proportions.There is something buzzing and light-radiating about the personality of a marked Sagittarius. Not in the centred, noble way of Leo, but rather more intellectual and expansive with a broader sweep. Think of the greek philosopher, enthusiastic and human, eager to share wisdom and information. Perhaps bohemian and untidy but always attractive in a frank, youthful and sunny manner.
In the world of stars, we see a striking Sagittarian in Woody Allen, showing a conjunction of the Sun, Jupiter (ruling planet of Sagittarius) and Mercury in the Archer sign. No clearer evidence can be imagined of Allen's bursting, visionary expressiveness, that seemingly uncontrollable communication urge of Jupiter in its own sign conjunct the planet of information and communication and the Sun. Another favourite of extroverted fire energy and jovial, frank Sagittarius energy is Bette Midler (Sun and Mercury in Sagittarius, Jupiter opposite the Aries Ascendant which also trines Mercury in Sagittarius). And not to forget Jimi Hendrix, (Sun, Ascendant, Mercury and Venus in Sagittarius opposed by Uranus in Gemini) a powerplant of artistic, high-flying electrical energy.