This is one of the most annoying ones to me. I recently almost booked a pair of ~2000 euro return flights for the completely wrong dates because the booking sit

This is one of the most annoying ones to me. I recently almost booked a pair of ~2000 euro return flights for the completely wrong dates because the booking site decided to (despite knowing our location and correctly setting currency, currency formatting and language) show it's date picker starting with Sundays. Only caught when I did a last sanity check before I clicked the pay button.