How many times have you been told not to leave something for the last minute, but when you did, it actually turned out better than expected? Well, Gmail's logo was the product of this situation — it was designed by Dennis Hwang (who's responsible for most of Google's doodles at the time) the night before Gmail launched. Former Google designer Kevin Fox tells the story on Quora: "The logo was designed literally the night before the product launched. We were up very late and Sergey and I went down to his cube to watch him make it."
What's even more interesting here is the logo itself. Fox notes that its letters are in two different fonts — the 'G' is in Catull, the same font as Google's logo, while the 'ail' is in Myriad Pro because Catull produces a strange-looking 'a'. We'll bet that you won't be able to unsee the font differences in the logo ever again — just take a look above.