I disagree with Dyske's answer.
In the first example, you are saying something that you know is not true.
In the second example, that is a subjective opinion. They can truly believe they have the best pizza, just like you hear people say they have the greatest wife or kids. It's a subjective opinion that they may truly believe in.
In the third example, that would be a lie because once again you are saying something that is not true even though it's hyperbole.
The way I under the definition of "lie" is that it wouldn't be a lie if I say something I BELIEVE to be true, but is factually wrong. If the police ask me to describe a suspect from memory I could truly believe I'm giving the correct description from memory and be factually wrong, but wasn't my INTENT to deceive the police.