The international mime for threading a needle involves holding the (invisible) needle upright in one hand while holding the (invisible) thread pinched between thumb and forefinger in the other hand. You bring the thread close to the eye of the needle, line it up, and then pull it back toward your palm without moving your hand away by bending your thumb and forefinger more, then reverse that motion to thrust the thread through the eye of the needle. Then of course you reach around to the other side of the needle, grab the end of the thread, and pull it through, fluttering your hand in an upward arch, almost like your hand is pretending to be a butterfly.
When you scrunch your thumb and forefinger up like that, the other fingers on your hand naturally move also, making the motion more visible to the audience. But keeping the rest of your arm and hand still gives your motion a lot of stability and accuracy. When you move your forefinger and thumb together like that, the thread moves in a nice straight line in the direction you want. Hold it close enough to the end of the thread, and the thread will not bend aside around the eye of the needle, it will just go through.
Thus making it, in truth, a really good way to thread a needle.