Peter laughs, shaking his head in amusement. "Being responsible is overrated. One shouldn't hurt."

But that look hurts a little to see, and causes his estimation of Gamzee to take a jump. He claps Gamzee on the shoulder encouragingly. "Thank you."

Those are the only words, but there's a wealth of meaning in the warm tone. Whether or not anybody but Peter could interpret, well, that might be another story.