We have all heard this saying before, either from a friend trying to comfort us or from one that is trying to belittle us for someone we are seeing. Sometimes, it provides a superficial comfort but when it boils down it doesn't change the feelings for that person. When you really care for someone, looks don't play as large as role as what made you start caring for them.
I don't decide who I care about based on their looks, personality is more than skin deep. I value how a person cares for me more than how they care for their looks. What I find attractive is their personality and their character, not the way that they style their hair. I would much rather have a relationship based around who they really are than what they appear to be.
Yes, physical attraction plays a role, but it is not everything. Ever notice how someone who makes you laugh seems more attractive? Or how quickly you got over how cute the person in your class was after getting to see how they were?
People are now too afraid to socialize all because they fear rejection based on physical appearance. They believe that anyone they find attractive is out of their league and that they have no chance with even getting to know them. Instead of striving and getting the person of their dreams, they settle with what they think they can get.
You are not too pretty for them and that cute person in line is not out of your league. Introduce yourself to that cute girl/boy in your class and get out there. There's nothing to lose but there is a possible gain. You never know until you try.
Choose who you care about based on how you feel, not how everyone else feels. If people don't like how they look, they don't have to look at them. At the end of the day that's your special person and that's all that matters.
Overall, live your life. Do whatever you want, love whoever you want and be whoever you want. Don't let society tell you how to live, you are an independent person and you have your own brain and body for a reason. You are under no obligation to let someone else control it.