Is the question referring to most people or to us as individuals? Because it is obvious that they're being used as a fashion statement in the "mainstream", or at least were for a while.
For me, it is functionality (comfort, well built) and sound quality first.
Ironically, my go-to earbuds are the cheapest ones I own, my Amazon ear buds that I paid $9 for. They fit well, have adequate sound quality (not perfect, but at that price who cares?) and have been extremely reliable. So function over SQ is a factor as well when it comes to having to take them in and out of my ears often while also not getting fatigued or soreness from them over time at work.