Driving down the highway you see a sign saying that your lane is closed for construction a mile ahead. Do you merge over now, or do you stay in your lane until the last minute? In the US at least, the normal thing to do is to merge promptly, and then get angry at the jerks who cut in at the last minute after zooming past the patiently waiting people who have already merged.

We think of this as a defect/cooperate situation: you can cooperate for common gains in which you share, or you can defect and increase your gains at the expense of others. Cast this way you should cooperate, but what messes this up is that it's actually better to merge late. What looks like polite cooperative behavior is actually worse for the group.

I think the solution here is the same as for buses: you should do the thing that has the best outcomes overall (take advantage of the emptied lane and merge late; squeeze through to the empty space at the back of the bus) and think of the misguidedly polite people as the rude ones.

Update 2014-05-22: I've become more supportive of the general value of building and maintaining the sense that strangers in your society are basically good people. Doing the efficient thing here erodes that sense, even if it would be better if we all did it. So in a case where late merging is very rare, one where the mass of early mergers are just going to resent you for late merging instead of joining you, your main effect is eroding that societal trust.