There are a lot of philosophical arguments that are pretty short but end with a strong conclusion. All of the arguments of this type I have ever come across are more or less easily refuted, and held at best by very few philosophers. These seem to either contain a well-hidden fallacy rendering the argument invalid, or contain an unwarranted premise making the argument unsound.
A great example is St Anselm's ontological argument, which is almost universally accepted as bad (though not everyone agrees on where the argument fails exactly).
I am interested in more or less short arguments having a pretty strong conclusion that are considered by the majority of modern philosophers to be both valid and sound.
By "strong" I mean "extremely counterintuitive, challenging beliefs that seem to you absolutely correct [when looked at from the eyes of an ordinary person, not a professional philosopher]".