That is 100% me. I've had many friends tell me someone was into me but I'm usually oblivious. I never want anyone to feel awkward or intruded upon and basically never act on such opportunities. I would love to, but my mind is usually partitioned off on a half dozen other projects, and at least one big rabbit hole of a curiosity. I have the capacity to shift my attention, but it takes someone being quite forward or otherwise remarkable in ways beyond a casual encounter or simple looks to capture my attention in a way where I might take spontaneous initiative. Basically, every girl I encounter is like my sister on a platonic level unless I have a clear indication otherwise. All my long term relationships are from social encounters with friends of friends where over time I could tell there was clear chemistry. Just saying, if you're a girl, being direct and forward is quite effective with some of us, especially the more quiet types.