If there are other advanced civilizations in the universe, and I can help be a part of finding them. Then this alone keeps me interested and running Seti.
Carl Sagan believed that there might be perhaps one million other advanced civilisations in the Galaxy. It was felt that should simple life arise on a planet, evolution would drive it towards increasing intelligence.
Yet, others would argue that simple life forms may very well be common within the Galaxy but it may not be often that it gets the chance to develop into an advanced civilisation like ours.
For us, letÃ¢â‚¬â„¢s hope that Seti someday is successful in finding evidence in Extra-Terrestrial Intelligence, as this would surely be one of the most exciting discoveries ever made.