Flight delays and cancellations are bad enough, but when you're on the plane and prepared for take-off, only to be removed from the plane, it kicks frustration up to the next level. Of course, there are valid reasons why someone would need to be removed from a plane, but other reasons, like the ones on this list seem more on the unreasonable side. Read on and see what you think.

Singing:
A woman on a plane at JFK Airport was removed from the aircraft and met by police because she was singing too loudly, reports the MSNBC website. The flight was scheduled to fly to Trinidad, but was delayed by the vocal disturbance. After airline employees asked her several times to lower her voice, the airline spokesperson Clint Williams said that the woman "became belligerent."

Being overly emotional:
 The website for the UK's Daily Mail reports a story of two sisters who were flying to visit their father after he'd had a heart attack. One of the sisters had been crying, and when she asked for a glass of wine. The flight attendant reportedly said, "I think you've had enough," even though the woman had not had any alcohol. They were then removed from the plane. The airline's spokesperson said that the sisters were removed after an altercation with the staff, and that they were put up in a hotel and rebooked on the next available flight.

Wearing the wrong clothing:
 Whether it's supposedly not wearing underwear or it's wearing overly-baggy pants, plenty of people have been booted from flights for "inappropriate" clothing. In one instance it was showing too much cleavage, while in another case it was a t-shirt with an offensive message.

Praying:
According to UPI a man was kicked off a flight because he wouldn't sit down until after he'd finished his prayer ritual.

Being overweight:
Two years ago, Hollywood director Kevin Smith was removed from a southwest flight after the captain deemed him a "safety risk" for being overweight. US Magazine reports that Smith fired back via Twitter. He was later given an apology.

Being smelly:
 After one particularly odorous passenger was asked to leave the plane when passengers complained, reports the ABC News website.