Dignity

The reason why Lolcats are funny but their canine equivalents aren't is all a matter of dignity. Dogs don't really have any, they are so eager to please that they will happily put themselves through all sorts of indignity to please their masters. Cats, on the other hand, won't. So when they are snapped doing something ridiculous it's several times funnier than it would be if they were doing it willingly.

Of course, cats can't actually blush. But they do a good line in washing themselves and ignoring you until you stop laughing at them.