Can someone tell me why do people do this?

[tydebine]

So I'm a sixteen year old guy who FINALLY got his first smartphone (Samsung Galaxy Nexus <3), in a world where iPhones are all the craze, I wanted to get something a bit obscure. Well I had to pay for the upgrade fee, the phone itself and have to give a bit of money to my parents monthly to keep it on. Ever since I got the phone (about a week ago) friends and others literally GRAB the phone outta my hands to play with it (games, Instagram, text messages,etc.)...some people even compare sizes with their phone because mine is gigantic! When I ask for it politely back, they completely disregard me where it comes to the point to me GRABBING it back outta their hands. Can someone tell me exactly why people do this? I have never done this; it's just plain rude. What is wrong with society these days?!

Thanks!
Tyde