From my experience (straight male, btw), while I have types/preferences in terms of physical characteristics as to what I find visually pleasing - its the personality that makes them attractive. Personality comes through in appearance - body posture, facial expressions, what the person wears, where they are, what they laugh at, how they move through the world - and will make someone who doesn't meet any 'type' ideals desirable.
Anyone else?
Look at a face - any face - for too long, and things get weird. The same way repeating a word over and over again alienates it from its meaning.
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Of course, it's probably quite a bit more complicated than that.
You know sometimes, between the dames and the horses, I don't even know why I put my hat on.