I recently came across a client that was getting a bunch of clicks from India via their Google Ad Campaign even though they were targeting the United States. It turns out they hadn't set their Location options to "Presence". By default Google has it set to "Presence or interest" which means your ad could be showing to someone who is just interested in your target location and not necessarily in your target location. Obviously, for most campaigns this is a problem if you're only wanting your ad showing to people who are in a specific geographic location.

For this client, they didn't do business in India so all of these clicks were wasted money.

Setting the location option to "Presence or interest" may make sense for a business that sells to tourists like maybe hotels but I'd argue it's still better to use "Presence" and just target all the locations you may get people searching for a hotel in X city. If you had a hotel in New York City for example, depending on your budget you're better off starting with locations somewhat close to NYC using "Presence" then slowly expanding out from there to scale your campaign if need be. Does a hotel in NYC really want clicks from India? Maybe but it's not the low hanging fruit and the farther away someone is the less likely they're going to actually be making the trip.