They also require rigorous training. There are many reports of manpad failures simply due to poor firing practices.
The one time I had one fired at me is an example. The NVA guy fired his Strella when I was considerably less than 100 yards from him. With no time to even arm up, much less acquire my heat signature, the missile just zoomed past my cockpit and went on its way. (Had he waited until I was half a mile away, I would not be here, probably.)
