The No. 1 rule of travel is pretty simple: Don’t piss off the locals. Most people know this — or at least they think they do, and they usually give it the old college try when it comes to not stepping on the toes of the people around them in another city or country.

Related: How to P*** Off a New Yorker in 12 Easy Steps

But what if you don’t know? What if you have no idea what irks the heck out of the locals? No worries; Yahoo Travel is here to help. With our How to P*ss Off series, we help you navigate those crazy cultural differences that can get you in so much trouble. So instead of getting bad karma and dirty looks, you can make friends and have a great time. This week’s episode is all about Mexico — everything you need to know to not rock the boat when visiting. We love our neighbors to the south, but do not piss them off. It ain’t pretty.