I spilled some coffee on some light coloured trousers on the way to the London office. The stain was centered right in my lap and I couldn't really go around like that all day, so I stopped and bought some cheap trousers at Gap to sort me out.

Pro-tip: Telling your local UK colleagues that you were running late because you stained your pants and needed to get new pants, and then offering to show people the stained pants is going to lead to some awkward moments.