My ex-girlfriend, an ENFP HSP who read all those books on HSPs, introduced me to the notion, and we both agreed that it seemed to fit. I haven't looked into the idea all that much, just enough of a cursory glance to get the general idea. I find the handling of it a little annoying, cuz it creates this whole group, and then treats them like they're special, but I think there is some truth to it, it just tastes a little bad in my mouth when it gets too frou frou (I was raised to despise shit like that). Anyway, I read that checklist on the link you provided, and answer yes to a bunch of them. The odd thing is, and this is true most of the time when it comes to my personality: in some circumstances those things will fit, and, in others, I will go totally in the opposite direction. I think it has a lot to do with being an enneagram 6, and being counterphobic. They say it about us all the time. We're... just... very contradictory. At one moment we'll be one way, and another we'll be the exact opposite. It has to do with whether we're gunna let the stimulus act on us, or if we're going to react and go against it. So, yeah, I mean, combine that with what I said about how I was raised, and sometimes I'll be just how you'd expect an HSP to be, and at other times I'll go straight to the center of the storm and dominate what's going on (whether that means taking control of a crisis situation, or just being the most powerful person in the room). Regardless of which approach I take, tho, my HSP qualities will always be there, either as something driving how I'm behaving in terms of acting like you'd expect an HSP to act, or driving how I'm behaving in terms of going in completely the opposite direction (while still possessing that same inherent sensitivity, just... kinda... shutting it down for the moment [I still listen to it, actually, I just don't let it cause me to "shrink away", as you'd kinda expect an HSP to do; rather, I use it to impel me to take control {and, interestingly, to put a huge emphasis on being fair, equitable, and just, when I do take control (being highly sensitive seems to make one highly empathetic, and this empathy stays with me still when I'm in a state of being powerful and expansive, as it's easy for me to remember what it's like to feel powerless and largely subject to external forces beyond my control [in fact, while I'd say I've always been this way, rather recently -- the last six months or so, especially -- the importance of this idea has become very conscious and at the forefront of my thinking])}]).