"Maybe I thought you were more mature than this." It'd sound a whole lot more like an actual remonstration if it didn't sound so approving. Maturity, in Gabriel's opinion, is a curse rather than a virtue.

It'd also be more chiding if Gabriel, knowing he's lost the element of surprise as far as throwing the gummy bear goes, hadn't decided to sneakily (or... not) try to stuff it down Raphael's collar instead. It's considerably more childish than he'd usually be, but being around his older brothers again brings that out in him. Little brothers - gotta love 'em, right?