It's very easy to be smug in the present, especially if we ended up being on the right side of history. We all know the internet is full of people doing stupid things, and this is never truer than when we look to its past (or when it's representing the past). Everybody has made mistakes that they have looked back on in horror, some of these are more cringeworthy than others.
This is especially true when it comes to predicting the future. The lack of foresight we are capable of having is truly astounding. Rare is the person who hasn't made a statement that has aged like milk, but not all of them are as public or as wrong as the examples below. Some statements there are no coming back from, and they can be difficult to forget as well. Always try to be careful about the things you say.