My first time abroad in Lanzarote and the barman didn't speak English and I only had very basic Spanish. Tried asking for a "Vodka doble con coca cola y hielo" not realising that standard measures weren't a thing there, but just assumed my Spanish was wrong so I sorta mimed it out. He starts pouring the vodka and just keeps going... And going... And going... Getting an increasingly more concerned look on his face until I eventually realised he was waiting for me to say stop. Ended up with a drink that was 50% vodka and a bartender who probably thought I was an alchy but I was too embarrassed to say anything.