Quite a few. It's my job to make sure that humans and aliens are able to live together without causing too much trouble. Sometimes I have to kill them, but usually not without provocation. Far too many times we've been drawn into something because of opposing sides of an argument decide to threaten us. My first contact with alien life forms was the Baltians in 1961. Only to do my job, we disappear. No fingerprints, no names, nothing identifiable. No family. Nothing. But it was important.