Among other things, iExist

Manier times a person comes to a point in life where they look at a person or a bunch of people and say, 'I could not have done this without you.' or 'I wouldn't be here if it wasn't for you.'
On the other hand, there will be times when some people will waltz into your life and say, 'You could not have made here without me.'

I understand the first feeling, it is mostly a feeling of deep affection and unwavering gratefulness.
The second, however, is just diluted narcissism. It ain't pure. People who are too rich and full of themselves often consider their roles in others' lives as more important than your role is in your own life. Pity is the only feeling I can spare for them. I have met such people in my life and honestly I do not regret meeting them.
Whenever you encounter people you do not get along with, you can just always walk away or you can stick around to see if it works out. You either make a friend or a mistake. Learn from it. Thank them for making you stronger. And let them be a messiah to others 'cause apparently without them people are doomed!
We are the most intelligent race and we choose to be THIS.
I exist because of my family, who gave birth to me.
I exist because of my friends/partner who stood by me.
I exist because I overcame the mistakes I made.
I exist because I want to exist.
Simple.