One of my favorite aspects of the first film is how it repeatedly depicts Wick commanding an almost mythical level of respect in the Underworld. The simple "Oh" uttered by Viggo in his call with Aurelio is a hilarious scene, but it's particularly brilliant for conveying in one word the sheer gravity of Losef's fuck up and Viggo's regard for Wick. And this respect is not just for John's talents but for the man himself, as Viggo later praises him for being "a man of focus, commitment, sheer will" while putting down his own son for lacking those traits. And throughout both films that deference is shown by every other high level player in the Underworld almost without exception.
But despite his legendary status, John Wick is such a grounded character. He's a force of nature but he never feels unstoppable like so many classic action protagonists. We see him beaten and wounded. We see him get his ass kicked throughout both films. He's shot, he's cut, he's stabbed, he's rammed by cars, he's thrown off of ledges and he's left limping after almost every fight with other assassins. He pays for those interactions in pain and blood, and because of this every encounter between Wick and an opposing force feels super fucking intense.