What is, being gracious at the net after defeat, a product of - largely?

Character? That would be ideal guaranteeing a uniform display of emotion across the board. But in real world, could it boil down to the opponent and the conditions at work, explaining the vast disparity on display throughout the tour?

For instance, Nadal is ALWAYS gracious when he loses to Federer - even on clay - but is snarly when (lately) it's been Djokovic across the net in the same position. Getting the pitchker?

Or Federer (after struggling initially - AO?) emotes a far lower degree of his sore loser self when losing to Nadal - on any surface - than he does against Djokovic.

So does it boil down to their own insecurity in reconciling the loss to a certain player dictated mainly by preceding conditions and history? Like Nadal doesn't flare up vis a vis Federer because he knows he owns Federer and an aberration here and there won't disturb the cart whereas the insecurity blows out of proportion when the same scenario plays out against Djokovic.

It's like the layers of an onion. Graciousness is a wonderful thing as long as it doesn't hurt - deep down. 

Federer losing to Del Potro at a Slam final evoked far less 'sore losingness' than it produced against Djokovic at a Masters 1000 final.

Translation: It's a matter of convenience rather than of character.