The sense of achievement

"You've got mail" film is one of my favourite. It's not brilliant but it has got enough great parts in it to make it very likeable. There are some great lines in it like:

The whole purpose of places like Starbucks is for people with no decision-making ability whatsoever to make six decisions just to buy one cup of coffee. Short, tall, light, dark, caf, decaf, low-fat, non-fat, etc. So people who don't know what the hell they're doing or who on earth they are can, for only $2.95, get not just a cup of coffee but an absolutely defining sense of self: Tall. Decaf. Cappuccino.

Innovations on  Microsoft's part are aplenty. To me, when it comes to Xbox 360 , nothing compares to introduction of game achievements. I think it is the genius idea that Microsoft should be very thankful for because in large part it got Microsoft where it is today in the gaming console market. I'm sure Sony would have been way ahead if they thought of introducing achievements for PS3 games instead of game trophies.

So why I'm wondering gamers like myself are so hooked in getting these achievements. Why is it that we get a smile in our face when we see that pop-up message appear: Achievement unlocked? Is it because deep down inside we're still like kids that like to be praised or just get a recognition for anything? Or is it because we went though some failings like almost everyone does and we somehow find solace in playing, escaping to another world, and get the sense that we "did it!" or "I can do this"?