Considering the sheer amount of resource exploitation needed to get decent space travel (and don't give me "There's a simpler way with different resources!", because I'm positive there isn't), I'd probably think "Holy cow, these people went green really quick."
And considering the amount of warfare, defense techniques and death that are required to scramble your way to the top of the species list (ie. be the species that would do space travel), I'd think "Wow, these people were pretty peace-loving, all things considered."
And considering sheer amount of social awareness that's EXPLODED in the past century, I'd think "Wow, these people were really starting to care for each other."
Then our crew would locate an old internet server farm, boot it up, go scanning through the files, and think "Wow, these people sure hated themselves. No wonder they went extinct."