I've said it previously, but the grind... It's like they've designed the game specifically not to be fun. Doing the same races, over and over and over, as the only remotely sensible way to earn enough money to buy a car you want (which is naturally then useless in any worthwhile races) just isn't fun.
The mindless, tedious grind leads to my other complaints:
The oblivious AI, that will meander all over the track / into you during the Tokyo 600, immediately losing you the clean race bonus (not that it tells you) despite the fact you can spend your whole time wall riding. The fact that is how they've arbitrarily defined the 'clean race bonus' for this one race too. Whereas Le Mans 700 a bit of contact is OK, but if you overtake under a yellow, which you have no indication of in VR, immediately lost the CRB. Or there's Sardegna of course. Where the CRB is seemingly guaranteed. Why are the conditions different for every race?
While we're at it, the stupid damage system where it just arbitrarily pulls to one side. When you're just miserably lapping the same tracks over and over to earn some credits, the damage model is nothing other than an annoyance, because the grind is dull, repetitive, uninteresting tedium, and oh look, you've been wall riding at 250mph and the car is fine, but oh no now you've nudged that wall at slightly the wrong angle so your car pulls to one side for a bit then just heals itself. It's just so poor that it becomes nothing more than irritating.
Annnd finally, the stupid wet wheelspin "physics" whereby the rear wheels somehow gain a sort of infinite momentum with dry tyres on a wet surface, a momentum so potent that changing gear, braking, traction control or throttle off makes no difference to whatsoever, but you can tap the handbrake so that the clutch is engaged and that instantly stops it. Again, it would be largely fine if not for the utter, utter repetitive tedium that is "the grind", that is the only way to realistically earn any credits in a reasonable time frame.
I have no problem putting the hours in to earn credits, the payout rate on the grind races is fine, it just needs to be that sort of rate per minute for every race, so that you can just choose any race you want and earn at the same rate, you're not forced down in to the same miserable 3 races over and over and over (or the Spa 1 hr of course) if some 20,000,000 credit car has appeared in the LCD for the first time in months etc.
Make Custom Races pay out 10x as much. That'll do, even with all the ridiculous ways Custom Races are still inexcusably broken.