UFO stories always bring out the jerks and comedians. We just don't understand that the crews are warned NEVER to land and try to communicate with Earthly humanoids. We are too emotionally immature, at the mercy of wild fluctuations in areas of self-control. We are, to them, akin to bright but neurotic children - en masse - and could never be trusted. Theyn witness our brutalities and 'class'differences, our wars, our bursting prisons, our cruelties to each other and defenceless animals, and realised centuries ago that landing here is the biggest no-no of their lives. If we, in our magnificent arrogance, really knew what they thought of us it would destroy every church and religion down here. More chaos would break out as it finally dawned on us that our lives mean less than nothing - it's all bloated ego and bluff. For every man who would invent something to enrich our lives there are a million who would smash it out of spite.
Our space invaders know all this, and with their far superior intelligence and depth ignore us - they just explore the geological developement, the atmosphere etc. The Earth is a cute place, interesting probably to them, but only to use, not to enjoy with its inhabitants. And who the hell blames them?