If we discovered evidence of life on other planets, it would likely be the most culturally/scientifically significant event of my entire life. Yet some people don't seem that bothered.
Okay, fair enough, I and many other people know that the chances of there not being life elsewhere are low enough to be considered zero but some people won't accept that until we have direct proof.
Once we have that direct proof think of the ramifications for not only science but technology, philosophy, religion, art. Some people can only seem to care about what will effect them as an individual on a day to day basis, which is their choice of course. However, I can't help but be moved by the profound thought that not only is there other life out there, but we humans from a little insignificant rock in an arm of the Milky Way went out there and we found it. I think it changes everything.