why people unfollow me on twitter?

[.]

K so I was really bored and decided to open a twitter account. I put up some quotes and stuff I like. Eventually I got about 11 followers but two of them unfollowed me. They have thousands of followers, so why do they bother to unfollow some of us? I get that Twitter is just a playplace for some and for others its a place where they desperately try to promote their business or products. I'm not taking Twitter too seriously and I admit its fun to read news updates on Twitter because they come in so fast. But I don't like to be unfollwed once I have been followed.