I agree, it's best not to take them too seriously--I remember when we were first using them, there were a lot of mistakes from people pushing the wrong one, especially on phones, because they're so small and close together. You can undo it for a short while, but after that you're stuck.
I don't like the "dumb" one. I think if you disagree with someone's position, you use the "disagree" or "dislike" buttons, you don't call them names. And I don't understand the "bad spelling" one. If someone spells badly we can all see that, we don't need someone to point it out. It just seems like another way to insult someone. If you have more to say than just, "I disagree with you," be straightforward and write it out, don't do the equivalent of giving them the finger and driving off.