Reductio Ad Ridiculum
Riddikulus! As all Harry Potter fans know, the way to defeat a boggart is to convert it from an object of terror to an object of mockery. While the spell clearly works, in real life, the appeal to ridicule is a type of red herring fallacy in which the opponent presents the original argument in a way that turns it into a mockery of itself, either by emphasizing the counter-intuitive aspects of the original argument, or by creating a straw man to debunk it.
An example of the first approach is the argument, “If Einstein's theory of relativity is right, that would mean that when I drive my car it gets shorter and more massive the faster I go. That's crazy!” It’s also true. The problem is that the effects are not easily measured at automobile speeds, but only become significant as the object nears the speed of light.
The second approach misrepresents the argument in order to ridicule it. “If evolution were true, that would mean that all the apes wouldn't be here any more, since they all would have evolved into humans!” That’s ridiculous indeed — but it’s not actually implied or stated in the Theory of Evolution.
Argumentum Ad Odium
The appeal to spite exploits existing bitterness or dislike in its attack. The various attacks on union benefits (such as retirement), particularly in government workers, relies on the negative emotions aimed at the target group as the primary justification for cutting back or cancelling previously agreed-upon benefits. “Why should people enjoy a comfortable retirement with my tax dollars?”
Wishful thinking is based on the premise “I wish P were true/false, therefore P is true/false.” You see this in a lot of superstitious behavior, from chain letters to the belief in UFOs. Personally, I think it would be really cool if aliens did in fact visit Earth — but that doesn’t make it true.