If you thought you were already flustered enough trying to make your way through the airport security while the staff yell at you to take out your electronics, your day could get a whole lot worse if you spot this one thing on your boarding pass.
We all know that airport security is a must for our safety, but there's no doubt the process of dragging yourself and your belongings through a never-ending security check at 5.00am isn't exactly fun.
However, there's an additional security check that you could be picked for if you're flying through America.
The four-letter code has been deemed as the 'kiss of death' by those who regular fly, as it indicated that you're most probably going to be held back for a while.
Talking to Fox News, senior aviation writer for The Point Guys, Zach Griff, said: "It’s a measure implemented by security authorities in the US to screen certain passengers with additional checks."
The code is 'SSSS', and it stands for 'secondary security screening selection'.
The expert added: "Selectees for this enhanced security are chosen in the days leading up to a flight when airlines share the manifest with U.S. security authorities.
“SSSS can also be entirely random, and there’s no way to know when booking your flight whether you’ll be chosen as SSSS."
But it's definitely the last thing you want to see after a long day of travelling.
One influencer who was travelling between Canada and America said the four S's are 'not your friend'.
They added: "If you ever get [SSSS] be prepared to be patted down four times over, harassed, made fun of in public and everything that comes with it.
“Those extra inspection can take up to [30 minutes] more, so obviously, that wouldn’t be nice."
However, the Transportation Security Administration doesn't quite have the same view - in fact the total opposite.
Instead, it has branded SSSS as a highly necessary security measure.
A spokesperson told Fox News: "Security measures begin long before passengers arrive at the airport.
"TSA works closely with the intelligence and law enforcement communities to share information."
It added: "Additional security measures are in place from the time passengers get to the airport until they arrive at their destination.
"In some cases, passengers are randomly selected for enhanced screening.”
So next time you're thinking of jetting to the US, keep a close eye on your boarding pass for the pesky four-letter code!