If you've never been on an airplane before, the thought of getting onto one may be very daunting.
Just ask the passengers on this list.
There are certain rules to follow when you're on an aircraft, but many of them aren't explicitly stated as they are pretty commonsensical, or so we thought.
Here are some passengers who have caused plane disruptions due to their unfortunate lack of knowledge.
1. Throwing coins into the engine for luck
A plane's engine is one of the most vital parts of an aircraft, and one would wish that it functions well in order to keep all passengers on board safe.
On Tuesday (June 27), a Chinese passenger delayed a China Southern flight CZ380 for up to five hours after throwing nine coins at the plane's engine for "good luck".
While eight of the coins missed, one was nestled in the engine.
Thankfully, another passenger spotted the act and reported it to the authorities, and the 80-year-old woman was detained by police at Shanghai Pudong International Airport.
The police later released a statement identifying the elderly woman with the surname Qiu, who was travelling with her husband, daughter and son-in-law.
And here we thought coin-throwing was only meant for wishing wells.
2. Mistaking the exit door for the lavatory
A man was given a five-year ban by KLM Royal Dutch Airlines in Sept 2015 when he tried to open the emergency exit door mid-flight at 30,000 feet above ground.
James Gray, the man onboard the flight from Edinburgh to Amsterdam, claimed he mistook the exit door for the toilet.
The airline authorities ignored his defence, however, and upon landing he was taken away in handcuffs to the airport detention center and slapped with a S$912 fine before being released.
He was denied access when he tried to book a flight back to Edinburgh as the five-year ban was immediately effective.
Apparently, this mistake might be more common than you'll think.
Early last year (March 2017), a woman onboard a China Southern flight also attempted to open the exit door after mistaking it for the lavatory.
Her sudden act deployed the plane's evacuation slide on the tarmac, to the horror of fellow passengers and crew.
She later explained that she was a first-time flyer, and did it because the queue to the toilet was too long.
Do all doors look the same?
3. Opening the exit door for fresh air
We all know that the air in an aircraft's cabin isn't exactly the most refreshing, but one man took matters in his own hands.
In March 2016, an unnamed Chinese man delayed his flight for 40 minutes when he opened the plane's emergency exit door for "fresh air" just moments before takeoff.
The China Southern flight CZ3693 bound for Urumqi Diwopu International Airport was due to take-off at 9.55am from Chengdu, but did not depart until 10.52am as the airport staff had to close the exit door from the exterior and re-examine the plane.
Sorry but it's an airplane, not a fresh-air plane.
4. Making bomb jokes
With terrorism a threat around the world, bomb jokes aren't exactly jokes.
Just months ago in April, a woman was stopped from boarding a Wings Airlines plane to Malang, East Java, when she made a bomb joke while departing at Ngurah Rai International Airport, Bali.
Titis AB, 28, had jokingly said to a security personnel at the departure gate that she was carrying a bomb with her.
She was later taken away by security officers to a room for questioning, and released after signing a statement to not repeat the offence.
Last year in Feb, an AirAsia flight from Kuala Lumpur to Banda Aceh was delayed after a flight attendant heard a passenger utter the word "bomb" on board the aircraft.
Turns out, investigations showed that the passenger in question had merely said "ada bom kot" (maybe there's a bomb). The plane was returned to the airline following the all-clear from police.
When will people learn?