Thinking he knows everything when he knows nothing, talking smack to Pops -- I should still kick him for that. [Although Whitebeard and Shanks worked it out and even Marco said Shanks wouldn't do anything too crazy when they were fighting.] Inviting people to join his crew when he knows they have loyalties elsewhere!

Annoying bastard, flaring his haki around young idiots who don't know how to defend against it... [Trails off into annoyed grumbles.] Then doing really great things like saving people's lives and helping set up memorials and then refusing to even accept a favor to pay it back...