User blog comment:Adventuretimegurl123/Theory of Ice King's Crown/@comment-5242921-20121127223508

One interesting theory is that the Crown warps a person's key focus. With Simon, his priority was to care for Betty and ensure she was okay, his love for her a strong point. So that love was warped by the crown into his obsession with Princesses.

With Finn, his sense of SAFETY was warped - his need to protect his family and the people around him - so he ends up endangering and maybe killing people to keep them safe, such as the Destiny Gang.