#3 Charles has Nerves of Steel
Attitude does play a role in how a sportsman performs; psychology is an important element in Motorsport, even if you can't see your opponent's face in the cockpit. Despite 2018 being his only season of F1 so far, Charles didn't appear to be daunted by the challenge awaiting him.
Just like when the likes of Max Verstappen, Michael Schumacher and Lewis Hamilton first joined Formula 1, Leclerc appears to be absolutely unflappable. It's not in a cold way either, he clearly cares about his colleagues, but despite his friendly persona, you can tell he's a fierce competitor when the visor is down.
Admittedly, Leclerc hasn't been involved in a controversial incident, but that has been down to his excellent and consistent driving, I can't recall an on-track incident he was heavily involved in (apart from the horror-crash in Belgium, but that wasn't his fault).
Yes, Vettel has shown these good mental qualities in recent seasons, but when the pressure's on, he's cracked, possibly because the level of expectation is much higher at Ferrari than Red Bull.