Captchas are the worst for this as a native British English speaker since they tend to be automotive, which is an area where British and American English differ

Captchas are the worst for this as a native British English speaker since they tend to be automotive, which is an area where British and American English differ wildly. Some are fairly self-explanatory because of how literal the American English terms are (pavement vs sidewalk, zebra crossing vs crosswalk) but some are a bit more arcane (central reservation vs median, bonnet/boot vs hood/trunk).