If you could choose one touhou to spend the rest of your life with, she'd satisfy your every need, cook you top-tier food and be the perfect waifu in exchange for that if you lose your temper even once during your lifetime with her she'll give you the most painful death there is to experience.
Note that losing your temper means getting pissed off at something trivial and it can happen everywhere when shes around and not around.
Who would it be /jp/?