Whilst I'm not saying the lobbing of the keycards and a smile (if you're lucky) is right, but I'd recommend reseting your expectations so that a day that should be really exciting for you doesn't turn sour. If you then get a better experience than the bare minimum you'll be happier and you still get to drive home in an amazing car.
BMW didn't do the big reveal for me at all as I posted above, so I was a little disappointed on the day, as they'd done it for a friend of mine a few times, so I had some expectations which they didn't meet, but still, the drive home was fantastic and other than posting in here about it, it's not something I've thought about since.
Hopefully you'll find the same for your Model 3, still makes me smile every time I give the fun pedal an enthusiastic poke. On my test drive, I had to apologise to the sales guy from Tesla for my involuntary swear when I floored the accelerator, just couldn't help it
It's time to YouTube! It's a nice UI so you won't struggle too much even if you do get a lacklustre handover, I'd suggest doing some YouTube research anyway to familiarise yourself