Once in college this guy I was just friends with asked me out to get ice cream.  I could tell he really liked me and I didn't want to lead him on so I told him I had a headache.  I know that he knew I was lying and I still feel guilty to this day about that!
Yes, I know thats what I was thinking.  I just don't know if I should have said the truth that I didn't like him that way instead of lying and saying I had a headache.