Looks always play a part, whether we want to admit it or not. Personality can increase or decrease it too, but if you look at someone and find them unattractive, you will not give them the time or day for a date based off of first looks. Simple as that.
You may get to know him/her and start to find them more attractive, but there's always, ALWAYS, base attractiveness.
no, it's not that simple and no I'm not just being argumentative. I'm going on experience, a woman did grow on me that much that I started looking at her completely differently