I live in a cold country, and each year I travel to one of my four favorite summer destinations: Valencia, Tel Aviv, Sydney or Porto.
I have a habit of visiting my grandmother when I return (same day or the day after) and when I meet her she would say, without knowing where I've been, "How was X?" (X being one of the four cities I mentioned).
She would often guess wrong, but I've noticed something strange. She has almost 100% success when it comes to Valencia. When I've been there she would always say "How was Valencia?" and she'd never say it when I've been someplace else. The rest of the time, seems like she's just guessing.
When I asked her how she knows, she only replies "because I'm perceptive, and you're irresponsible".
Can you help me figure out how she does it?