I understand it might not be a universal answer or something which always would do it, but in general what does it take to mentally intrigue you?
Firstly, someone who is a conversationist
And not just small talk. Someone who can easily bounce around various topics.
From funny, memories, flirty, life's deepest questions, etc
(I struggle with people of few words and soon become disinterested.)
Secondly, someone with a lil edge and mystery
Thirdly, someone who can keep pace with my mischief and banter. I love someone to give shit back to me. Feisty and bratty people
And lastly, someone who lets me know they think about me, out of my presence.
It's a sense of euphoria, for 2 people to long for each other's company.
These type of things is what draws me to someone. If things like that connect, they don't have to try and be sexy. Chemistry is naturally there.