This is 50 percent accurate...and I understand what it means.
What I think this is implying is usually the people who you "get along" with are going to have similar personalities with you...thus creating the attracting connection.
So, it allot of cases people who meet people with those similarities...have shared or are going to share similar life experiences.
But the reason I agree on 50 percent is because...I can't seem to comply how the possibilities of a person being "physically" attracted to someone creates this deep connection. It just seems inaccurate. In my life, I have meet multiple men who have absolutely nothing in common with me..but think of me as f*** worthy. I myself, have seen attractive dudes that I have absolutely nothing in common with...but I would like to f***. I just feel this statement relates to emotional or mental connection..not always physical. I can't guarantee from appearance how a person will behave...for me and I bet loads of other people..it isn't possible. This is where that "Don't judge a book by its cover" theory comes into place.
(Attraction has multiple ways of conducting itself...physical, mental, emotional, etc)