Why isn't it ending? Your task: To write a program that should obviously terminate, but it never (to the extent of a computer crash) does. Make it look like it should perform a simple task: adding numbers, printing something,... But it just gets caught in an infinite loop. 

Try to make your program very clear and simple, while it actually will get stuck in an unforeseen loop. Voters: judge the answers on how "underhanded" they are!

This is a popularity contest: Be creative!
Javascript

var x=prompt('Enter a value under 100');
while (x != 100) {
  x=x+1;
}
console.log('End!');



   prompt() returns a string and the loop appends the character '1', it will never be equal to 100.