I think about this pretty much everytime I go back to play Rocket League.

For what it is trying to be, for what games are to me, it always amazes me how just pitch perfect it is in pretty much every element of the game. It's not a game I would consider as a greatest ever or my personal fave, it perhaps doesn't resonate on an emotional level or have that sense of mystery and adventure that often is inherent to the all time great 'experiences'...but I do keep wondering if it's perhaps the most faultless piece of game design and execution.

The controls are perfect - responsive, accurate, simple to pick up but with plenty of depth. Even the way they deal with camera controls, which could be a big problem for this kind of game, is a solution I don't think could be bettered.
The gameplay is perfect - it's fast, it's fun. It's simple enough that kids can pick it up and play straight away, but with a subtely and complexity to it that even after years playing it I'm totally shite in comparison to the advanced level players.
It plays fair - sure there are flukes and unlucky bounces and rebounds, and it hurts when experts fly through the air scoring unbelievable goals, but it's always fair. There's no sweaty goals, no cheat moves you can't stop, nothing that can't be stopped if you're in the right place and time.
The level design is so clever. The layout of the boosters and the design of the arena is such that you can navigate around without needing to look where you're going. The distance between boosters and the timing of their regen just feels perfect - always just in reach, never too easy to be fully boosted all the time, just awkward enough that sometimes you're stuck with no boost for a few seconds and it feels like forever. All the other little visual touches to help you navigate the game world too (like the little outline and lines on the ball to help track it in 3d space etc)
Every goal feels great. Doesn't matter how you score it, it's either a hilarious fluke or something to be proud of no matter how simple it appears.
It's multiplayer and it's super slick in all the modes. on your own or with 2/3/4 friends? just party up and go and you'll probably be in a game in seconds. Regular tournaments too if you want to test yourself.
Graphically it's sharp, colourful, detailed and most importantly smooth and fast. It's also always very clear in visual feedback.
Audio is judged spot on. Some of the music is really great, it hasn't bored my yet, and even the OTT commentator manages not to be annoying after all this time.
The in game quick text chat is a brilliant way to have a bit of banter/respect with opponents without the whole thing becoming a bitter slagging match on voice chat.
It's even free now! And you never feel like you're missing out anything gameplay wise by not buying stuff.
The default mode is king. It's perfect and the one to come back to. But they do keep adding free extra modes and stuff for a bit of variety.
You can jump in for a quick 5 minute game or play for hours and it never really gets boring (unless you hit a run of super opponents who make you weep at your own failings - expressed by calling them cheating flying ****s obviously - even then you can just switch mode)

If I was being really picky, the only thing i can ever think of as a negative is that after a casual mode match, you can't quickly move on to new opponents. Clicking ready just seems to do the same as clicking rematch, leaving you waiting for opponents to decide. But that might be cos I only ever play in parties rather than joining randos, and I guess nothing can be totally perfect

Anyway, once you all agree I'm right and that it's Rocket League, we can maybe open the discussion to see if anyone wants to make the case for another game.

Preferably not Tetris as that seems too obvious