I was meeting a friend for dinner in Barcelona one night and got a text message that he was running late. Since he was one of the people with whom I spoke English, Spanish and Catalan, and I wanted to know how late he’d be, I texted back, “ETA.”
To me, this primarily means Estimated Time of Arrival, a significantly common acronym. Being a native Spaniard, he thought I meant Euskadi Ta Askatasuna, the Basque separatist group. He called right away to make sure I was okay since he’d been in Barcelona when ETA bombed a shopping center in 1987.
Fun (?) fact: that very same shopping center was my first grocery store in BCN when I lived on Carrer d’Escòcia.