How many hours from Vietnam to the US?

Ugh, that flight from Vietnam to the US... it's a beast. I remember looking it up once because, well, wouldn't it be amazing to just hop over there? Anyway, I found out that a non-stop from Hanoi to San Francisco is like, thirteen and a half hours. 13 hours and 35 minutes to be exact, if I recall correctly. Can you even imagine being cooped up on a plane for that long? My longest flight was only six hours and I was practically climbing the walls! Of course, if you're not going to San Francisco, it could be even longer, right? Like, where else would you fly to? New York? LA? I bet those flights are even crazier. Just thinking about it makes my legs cramp up!