system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: why is it so hard for Tesla to get their fit and finish up to the standards of other car companies?

Yes I have searched and I couldn't find an answer. 

I can understand why perfect paint jobs are hard, they just are. However, with things like panel gaps being bigger in some spots, or interior panels not lining up correctly, how does that happen? I would think that all these body panels and interior panels are stamped or molded on the same machines, so shouldn't they all be exactly the same and therefore fit together the same?
gpt
Cars are incredibly complicated assemblies. The major traditional manufacturers have spent decades working out how to do this. You are correct that stamped parts coming off a tool will be very similar, although tools do wear over time. The variation can also occur when parts are assembled. If you have 0.5 mm variation in how two parts meet, an assembly that has ten parts could result in a 5 mm variance, which would be enough for a hole not to match up with a mating part.