Well, we all have no idea of what will happen on a given day. Where I am going with it is to get you thinking, what would Homo Sapiens be like if we mixed our culture the culture of those whose species was born another planet. Would there be peace among the Earth, would we all fight for alliance with this superior power, would we attack them and start a war, or would they attack us and, Like on the popular show "Falling Skies," take over the Earth, driving humanity to extinction and using us for experiments and military force.
You don't have to get me thinking. I've thought about this for decades. I have no idea what type of aliens we might first meet, if we ever meet any at all. My best guess is that we'll most likely run into microbial life (with no sentience) of some type, or if it's sentient, some form of mechanical life which is so far beyond us in technology and knowledge that we may not understand anything about them(or their motivations) at all.
As for how humanity reacts, I suspect we'll either band together (if attacked) or largely ignore it (if they are not a threat). And if they have knowledge or goods to offer we'll probably squabble over it and worry that someone else will gain knowledge (power) that another group doesn't have. Basically the same human responses we get to all situations, just on a larger scale.
If we meet something with vastly superior technology and knowledge and if they do decide to interact with us (without obliterating us), then I am certain that our entire culture will be completely overturned within a few generations just from exposure to their knowledge and tech.
The first chapter of the novel Singularity Sky by Charles Stross describes the most likely scenario quite nicely. If you get a chance to read it, it's well worth your time.
The novel follows the ill-fated military campaign by a repressive state, the New Republic, to retaliate for a perceived invasion of one of its colony worlds. In actuality, the planet has been visited by the Festival, a technologically advanced alien race of "datavore's" that rewards its hosts for "entertaining" them by granting whatever the entertainer wishes, including the Festival's own technology. The result is that even the most insignificant person can get anything they wish for... unlimited food, housing, tools, and weapons (of devastating power). This causes extensive social, economic and political disruption to the colony, which was generally limited by the New Republic to technology equivalent to that found on Earth during the Industrial Revolution.
Just ask yourself what our world would be like if everyone had their own atomic weapon...