"Cut out all these exclamation points. An exclamation point is like laughing at your own joke"

This quote by F. Scott Fitzgerald is a suggestion to be mindful of how we reveal ourselves. He is suggesting that utilizing a lot of exclamation points is like laughing at your own joke, which can be viewed as a sign of insecurity. He is warning versus overusing exclamation points, as it can stumble upon as insincere or perhaps desperate. He is also implying that it is better to let the material of your words speak for themselves, instead of depending on punctuation to highlight your point. In other words, it is much better to be positive in your words and let them stand on their own, instead of relying on punctuation to make your point. By eliminating the exclamation points, you are permitting your words to speak for themselves and come across as more sincere.