In Jetpack Joyride, there are a few missions about having near misses with stuff. What, exactly, is considered a near-miss?
A "near miss" is when you go near enough to whatever the specified object was but not get hit. For zappers, for example, just fly extremely close to one end and it will count. If you have an active quest for this, you know you've done it correctly when you see an exclamation point pop up and hear a "correct" sound, for the lack of a better description.
You have to go close to it, but don't get yourself killed. With horizontal zappers, if you stay close enough for long enough, it can count as 2 near misses.