One of the things that really makes me angry that I understand is entirely irrational is when people say "guesstimate". I am all in favor of combining words that share syllables in order to create two different meanings, except in this case you're combining words that share the same meaning. You're not fucking clever, you're just a redundant fucking clown.
Either say "guess" or say "estimate". When you say "guesstimate" it hurts my fucking ears. They mean the exact same thing, at least in the limited context that you understand the word "estimate" to mean. I'm not trying to insult Americans who understand the subtelties of the English language, but I am trying to insult the subset of stupid Americans who use the word "guesstimate". You people suck. Stop it.