will you be my friend?

it's so easy making friends as a kid. you go outside with your pogo stick/basketball/tricycle/barbies etc. and start chatting to the other kids on the street. before long, you are out every day playing cops and robbers, street hockey or skipping. school days are just as easy - 100s of people to choose from and lots of way to socialize. why is it harder as adults?
how does one make friends as an adult. it's hard! i know i've only been here a week but i'm getting restless (however i did have a great night dancing on friday at the marquee). i really wish it was ok to walk up to someone and say "hey, wanna be friends". maybe i should and see what happens. i wonder how i'd react if someone did that to me.