My memories of the Mona Lisa is of a rather small paint behind dirty glasses with a large group of japanese tourists grouped in front of it and I simply didn't have the patience to wait and I just really glanced at it while passing by.
Also like most paints of its age, it is seriously damaged, colors aren't the original one and paint is cracked. I wish there was a way to actually enjoy in person those paints as they were when they were delivered to their customers.