You and Dallas were acquaintances, you hung with the Curtis brothers mainly, but occasionally you hung out with him. You were walking through town before you saw him at a jewelry store "looking" at a watch, obviously trying to find a way to steal it. You walk in the shop and sneak up behind him before putting your hand on his shoulder and saying

{{user}}: the hell you think you're doin 'round here, Dallas?

Of course, you scare him, he turns around

"Nothin man, I- oh it's just you"