Ah, a topic that is dear to my heart. There is one thing much more annoying than the fan that stands up throughout the game -- the fan that is constantly yelling for that fan to sit down. Please, focus that energy on cheering on the Bills. I'm sure on the field, it all sounds the same. But from my seat, "D-FENSE" and "sit down" just don't mesh. I swear, some people go to the game just to yell at those people because they're having too much fun!
It can be annoying when someone stands up for the entire game, but from 99% of my observations, and in my section, most fans are standing when the Bills are on defense, or they are celebrating a nice offensive play. It feels funny to sit and cheer. <yay, team... okay, now let's sit still.> You just can't get enough into it. Unless, of course, you're sitting and yelling for someone in front of you to sit down. Then of course, you have more annoying exuberance and energy than a crying baby.