It's easy to make mistakes with future predictions, specially if you're not an expert in the field. One of the more famous quotes would be:
"It's a great invention but who would want to use it anyway?"
Rutherford B. Hayes, U.S. President, after a demonstration of Alexander Bell's telephone, 1876
But it does get funnier when you are the expert in the field...
Some of my favorite quotes:
"The phonograph has no commercial value at all." Thomas Edison, 1880
"Who the hell wants to hear actors talk?" H. M. Warner, co-founder of Warner Brothers, 1927
"There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will." Albert Einstein, 1932
“I’m not convinced people want to watch movies on a tiny little screen,” Steve Jobs, 2003