Honestly? Shared life goals and morals. I have very little in common with regards to hobbies with my partner but we both want the same things in life and have a timeline in mind to achieve those things. 

Love and attraction will only get you so far in a relationship. For some people it might be enough but there will always be a tension or resentment if one of you doesn't get their way and feels they wasted their time on earth or wishes they'd achieved something different.

Having the same life goals and general morals is far more important than superficial things like hobbies.