With this being said, there can be a drawback. For instance, if you're an athlete and you are competitive in nature, you might find the similarities too alike. What I mean is that if you're both competitive and won't admit defeat in argument, it's hard to continue the relationship. Instead, someone who is less competitive and understanding might be a well suit. So take this into consideration when dating someone who's much like you.
Also, another thing to take into consideration is that you might change over time. Interests and personalities don't always stay the same so make sure that you really like the person and who he/she is.
- both young, both rich, both famous, both singer,...
Besides, few setbacks that may occur, similarities-attract theory is spreading wide and more and more people are dating those who are similar to them or have similar likings.
For me, I apply the similaraties-attract theory when it comes do dating quite often.
For instance: I love food, sports, dance, music etc. So I am interested in someone who also appreciates those things. Also it's very helpful to be with someone who understands what you're going through. So dating someone who is in college is easier for me than dating someone who's not. That way we understand our work load and schedule.
As you can see similarities can bring many benefits to the relationship and also help it develop further.