YouTube - Leave Me Alone... Sometimes (ProteanView)
I disagree however that extraverts NEED to engage people. Would you agree?
Being an extravert myself I am perfectly comfortable being alone and not engaging others but I prefer that I do because for me (may be an SP thing) it keeps me from being bored, that said I rarely care for random small talk with strangers
Though that may actually be a bit of an ESTP thing... As Keirsey says: "Promoters understand well the maxim, "He who travels fastest, travels alone," although they are not likely to be lonely for long, since their boldness and sense of adventure tends to make them highly attractive to many other people."
Questions to the extraverts,
Do you feel comfortable being alone?
Do you feel the need to constantly engage people?