The "smile" gets bigger or smaller depending on the drink's... what, potency? Pepsi has gone through a LOT of different looks over the years, but I think far and away my absolute favorite is the white can with the old logo from the late 80's/early 90's:
Simple. Elegant. Perfect. If you like Pepsi. I'm more of a Coca-Cola man.
Here's some other recent beverage makeovers.
When I was in high school, Nestea looked like this:
That looks like a fun drink! Now, Nestea looks like this:
That looks like medicine.
And how bout Sierra Mist? I only started drinking this a couple years ago. It looked like this:
That also looks like a fun drink! Now it looks like this:
That looks like a horror movie.
I feel like every time they redesign beverage logos-- or any logos, for that matter-- I like the new logo a lot less. But I suppose logo changes are necessary... for time travelers to be able to triangulate the approximate year in a pinch.