I used to hope I'd live long enough to see that. But then I thought about the nature of humans.
If I do live to see some kind of Avatar-style encounter between newly spacebound humans and another culture that hasn't developed quite as far, I will witness the greatest killing in recorded history. I will witness the first tentative anthro(?)pological research into this wonderful new species, followed shortly by the discovery of something they have that we want, and our culture punchfucking their culture straight into the history books. "We encountered a wonderful pre-industrial alien species, studied their art, music, and culture, then discovered we can get a killer buzz from snorting their powdered lungs. Their existence lasted eleven years after first contact. We keep a few specimens in zoos, but for some reason, they've lost the urge to breed."
If I live long enough to witness the encounter between a more advanced species and ourselves, I just hope I have enough time to pull out a lawn chair and enjoy the lights as their orbital bombardment commences. Such a species would rapidly recognize that if ours were allowed to spread, it would be to the violent exclusion of all others in our vicinity.
It's a scary thought, but if humankind wants to survive in the long term, it needs to think about Darwinism on an interstellar scale. It does want to survive, certainly, but whether its survival is a good thing? That's a question for the Galactic Council of Enlightened Species, not us.
Humans by nature treasure life, unless it's not our own, or our immediate family's. Beyond that we're perfectly willing to kill other forms of advanced life, as hilariously demonstrated by Terry Jones and his most recent movie. Introduce the element of the alien other, and we'll be lining up to find reasons to bomb the six-legged fuckers.
Imagine a scenario: the first human interstellar exploration vessel encounters a planet with sentient life. They're iron-age, but their advancement is faster than ours. They went from stone to bronze to iron in a third of the time humankind did. They pose no threat now, but they might in a few centuries. Now tell me that every military planner on earth didn't just get started on a giant planet-killing bomb project, to nip the issue in the bud before it becomes significant?