Ive seriously been wondering lately where bethesda got this little guy with yellow hair? Haha

I don't know if anyone will be answer this but, ahhhh then we can just speculate.

P.s oh and did you notice he is like always grinning haha

Vault Boy has been with the series since the first game.

http://fallout.wikia.com/wiki/Vault_Boy#Behind_the_scenes

Bethesda got it from the original games (they didn't make them). They came up with him to create some sort of icon that fits the theme of idealized 50s America.

I used to think that it didn't fit the series at all

I saw a picture of the vault boy doing a thumbs-up on the door of a restroom in an Italian restaurant alongside the phrases, "Please leave our toilets as you would like to find them, thank you very much". Go figure.

Maybe they meant 'and not like you find them in Fallout'!

From the Wiki:
The character was originally designed by Leonard Boyarsky, based partly on Rich Uncle Pennybags from the Monopoly board game[4], and then drawn for Fallout by George Almond for the first few cards and then by Tramell Ray Isaac, who finalized the look of the character as we know him today. Brian Menze is responsible for all new Vault Boy images in Fallout 2 and Fallout: New Vegas. The Fallout 3 images of Vault Boy were drawn by Natalia Smirnova and the Fallout Tactics ones by Ed Orman.[5]

http://fallout.wikia.com/wiki/Vault_Boy

I'm sure that was what they meant