82. assignment (incoherent light source)

If I were to take an incoherent light source such as lamp and measured the incoming light at a given point in space some distance from that lamp, surely, the number of light waves at the minimum point on their oscillation and the number of light waves at the maximum point on their oscillation would be equal. And so, would we not expect them to interfere destructively giving a net effect of zero light, or close to zero light? What I am trying to say is if the lamp emits lots of random beams of light won't they all just cancel giving a net effect of zero? Clearly, the lamp still appears bright so where does this logic fall down?

Video description:
https://youtu.be/5vQXuvABu84