I'm guessing that civilizations on some other planets probably have a much easier time of colonizing space than we do. We have the misfortune of finding ourselv

I'm guessing that civilizations on some other planets probably have a much easier time of colonizing space than we do. We have the misfortune of finding ourselves in the only vaguely-habitable rock in our own solar system, but some other systems must have multiple habitable planets, even multiple life-supporting ones. Imagine if the moon had been several times bigger -- it would have an atmosphere, and thanks to panspermia might even have picked up enough life from Earth to give it a breathable atmosphere. The Apollo Project would have immediately been followed by a project to kill and eat the local wildlife to see what it tastes like. Or suppose we'd evolved on a moon of a Jupiter-like planet in the habitable zone -- there'd be a whole bunch of other equally habitable moons just a short flight away. Instead we're stuck on a big rock, looking at a bunch of other rocks which are fairly useless to us. Sigh.