Nature has taken millions of years of experience and distilled it into our emotions/instincts. Any genes that made people stay around to pet the cute saber tooth tiger? Gone. Any genes that led you to hang around and ask an aggressor about the weight and/or density of his club (logically speaking, it could be styrofoam . . . )? Gone. Any genes that allowed you to leave your baby alone on the ground while you went to see your friend 3 caves down? Gone.
Has anyone ever used logic to decide who to be friends with? Logic is good for figuring out when our emotions are being used to trick us (i.e. in court when you show a video of the poor injured worker playing volleyball the previous weekend) but it is secondary. So, yes, appeal to the emotions first and then use logic as a secondary reinforcer.