Which pizza place? Was this in-person or online? The animation on Stripe's launch page is pretty much what buying things with Bitcoins is like for me: https://stripe.com/bitcoin.
Pembury Tavern. Last time I went there they weren't advertising "pay with bitcoin" any more, only "send us bitcoin tips", which avoids the problem. Maybe the tech's gotten better (this was a year or so ago now), but from here that looks like at least one early adopter who's given up.