Harry and Luke probably bumped heads at times. Harry’s such a liberal, that there were probably heated discussions on certain subjects, probably having to do with guns or pot or why he’d be president of the supernatural world’s PETA if it existed.
But then they’d agree to disagree and be joking again 5 minutes later.
And Harry had so much love and respect for him and what he does and the sacrifices he’s made. He was also the first to stand up and applaud at his commissioning.