What's the only thing worse than having two dead team members, an approaching wave of special infected, and a fresh sheen of Boomer puke on your person? Having to suffer all those things while also -- fighting -- server la -- tency issues. Fortunately, that experience has become less common, as Valve recently did a bit dusting around their network infrastructure, reducing lag during bouts of Left 4 Dead 2 on Xbox 360.
Of course, even without the lag, you're still going to die. But at least now you'll be able to see where it's coming from. (Hint: It's probably from those three oncoming tanks.)