Many things can create one, ...
Many things can create one, it can be of any shape or size, it is created for various reasons, and it can shrink or grow with time. What is it?
No room at the inn...
By the time the sailor pulled into a little town every hotel room was taken. "You've got to have a room somewhere," he pleaded. "Or just a bed, I don't care where."
"Well, I do have a double room with one occupant - an Air Force guy," admitted the manager, "and he might be glad to split the cost. But to tell you the truth, he snores so loudly that people in adjoining rooms have complained in the past.
I'm not sure it'd be worth it to you."
"No problem," the tired Navy man assured him. "I'll take it." The next morning, the sailor came down to breakfast bright-eyed and bushy tailed. "How'd you sleep?" asked the manager. "Never better." The manager was impressed. "No problem with the other guy snoring?" "Nope. I shut him up in no time," said the Navy guy.
"How'd you manage that?" asked the manager.
"He was already in bed, snoring away, when I came in the room," the sailor explained. "I went over, gave him a kiss on the cheek, and said, 'Goodnight beautiful,'
...and he sat up all night watching me."