Surely there is life elsewhere in the universe. I trust that it is actually ubiquitous. But intelligent life, such as our own, is presumably a rarity. By our definition, there is only one intelligent species on our planet. One less genetic mutation and we could be just another bonobo swinging through the trees, and there would be no intelligent life or civilizations or web sites dedicated to dissing the concept of gods.
So if we assume our own experience as "normal", we can extrapolate and say that there may be many planets with life that have no intelligent species. Of course, since we are merely taking a snapshot of our own planet as it currently exists, we don't know how many intelligent species might exist on earth in a million years. Or ten million years. So it may be that we are the first and that many other planets, older or otherwise in a position to be more advanced, evolution-wise, might have multiple intelligent species.
But whether one or a dozen, they may be intelligent enough not to f**k with mother nature, and hence they may do their best to stick to natural lifestyles, rather than the agriculture/trade/kill people route. And we'll never know they exist because they won't be calling us.
Or they may be intelligent enough and active enough to modify their planet and biology as much as we have, or more. If they've done it a little worse, they won't survive long enough to become our friends. If they've done it wisely, overall, then they may not want us for friends.
Hopefully it is both hard and unusual to mess up the ecosystem more than we have. And hopefully the species that become intelligent on other planets are a bit less aggressive.
The one thing that we tend to forget is that the peak period of any given intelligent civilization may not coincide with the peak period of other relatively nearby intelligent civilizations, so there may have been some great world circling around what we now call the Crab Nebula or something, and it is now simply gone. And it probably was gone for millions of years before the star went supernova, because things go bad for planets long before big explosions happen. While it is surmised that the earth will get swallowed into the sun when it grows into a red giant 7.9 billion years from now, but life on earth will cease to exist other than simple one celled critters in about 600-800 million years because of changes in the sun and the unsurvivable global warming that results. If humans can't figure a way to get off the planet long before that, we are toast. Literally. And if that has already happened to civilizations within contact range, we'll never know it.
But you can safely assume all civilizations will have problems. If not with themselves, then with earthquakes and asteroids and extreme weather. And maybe ray guns from other less well adjusted beings living on nearby planets.
In some instances, there may be other intelligent species in the same solar system, and hence intermingling might be relatively easy once one of the worlds gets space travel. But holy crap, can you imagine the dangers of two disparate ecosystems colliding via visitation. The best outcome might resemble the horror of North American natives meeting European germs. The worst outcome could be the end of all native life on at least one of the planets. Being intelligent species doesn't mean you are also immune to unknown microbes.
For that reason, I suspect that most direct intelligent interactions between civilizations from different world will be done by robotics and other automation rather than face to face contact. Or whatever it is they have on their bodies that resembles our faces functionally. If anything.
Man those guys could be weird.
Of course we may actually be alone, at least in our galaxy. Right now, for all practical purposes, we may as well be.