which one do you believe in

First option

It's easier to get along with someone that have things in common with you I guess :)

A combo of the two like a Venn diagram.

I feel the first, if two people have more similarities they'll get along better.

for dating purposes wither way is fine but for a long lasting relationship/marriage probably the first one

similarities

opposites may attract at first but i think they lead to a clash eventually

Neither. You are meant to be if you are meant to be.

First, based on experience.

I like it when my partner is a little bit different from me especially the way he thinks.

I always like discussing things and exchanging different opinions.

So I guess it really depends. Maybe a little of both.

Similarities make a tight couple

Quote from DMV2DMZ

A combo of the two like a Venn diagram.

I agree.

I don't get along with people that are too much like me and with people that are too different.

Opposites attract. My partner and I are so different yet have managed to stay together for 20 years and have an 18 year old daughter. He is an extrovert, I’m an introvert. The only thing we have in common is we both like cats. I stay as he is my mental health rock, without him I’d be screwed or dead.