Enemies become friends

Can enemies become friends ? , Can friends become enemies ?

You'd see people who don't like each other at first sight and then they become used to each other and then they'd like each other and then they become friends , and it is the opposite ...friends liking each other then hating each other, and then there is the love/hate continues cycle .Can people of different personalities be friends with each other , or is it "A flock of birds fly together "?.

I used to hate some people , then we worked together got used to them and started becoming friends .