You haven't even read any fan opinions or user reviews?
Well.
Ever gotten kicked out of the game because you lost connection with EA's Servers for no good reason? Maybe in the middle of a long race/cop chase or in the middle of a build, with all that progress lost? Some people couldn't even connect for hours on end and had no game to play.
Ever had real life interrupt you with something unplanned-for and urgent in the middle of a long race/cop chase, only to find out you're unable to actually pause the game and you end up shitouttaluck?
Ever accelerated out of a turn with a laggy turbocharged car only to find out your car... wasn't accelerating because the transmission upshifted early or held on to a higher gear for too long? Because there's no manual transmission option, the only solution is to slow down by 2 gears to get 1 downshift, or just use a supercharger instead.
Potentially game-breaking flaws aside:
The icon of rice, the Honda Civic, has no body kits and no rear bumpers. Many tuner cars, not just the exotics/muscles, are bereft of customization options. There are also some strange restrictions to customization. For example putting on a body kit will lock out spoiler, hood, and exhaust customization, among other things. Some body kits don't change the spoiler at all, but some put on a horribly ricey spoiler that you're stuck with if you want the body kit on. WIP customization spreadsheet:
https://docs.google.com/spreadsheets/d/1seHjNYjEcYhtxANA9sI4x4UaPXBOMy5tl66sAl5D5Ck/edit?usp=sharing
Many players are reporting the game can't even hold 30 fps, and are also complaining about blurriness/grain, permanent rain, shitty story/characters, 5-car garage limit with no outside-of-career garage for free customization, rubberbanding, pathetic police, and location-based time-of-night so crossing certain imaginary lines will switch the skybox from pitch-black to dawn, or vice-versa, in a second.
It's nice that you're enjoying the game, but those are some of the complaints so far.