This is literally exactly how I feel. I couldn’t have put it into better words. I simply can’t drink from two liters because it’ll go flat, just like the smaller bottles.I always buy cans to keep at home. They are the perfect size for me to drink with a meal. I also think soda tastes a little bit better out of a can than a plastic bottle. If I must buy a bottle, like out of a vending machine, then I will but most of the single serving bottles are too big and start to go flat before I finish them. I also never buy the big 2 liter bottles for the same reason. As soon as you open them, they go flat so they're only good for one use.
Cans more often than not. I’ve had soda for so long that I can tell the difference in taste between cans and tap, and tap can definitely taste bad at some places.