Girls would prefer a tall guy probably, but they would also probably prefer a 9" dong. It isn't something that's usually an instant deal breaker. Confidence is key. Be smart, funny, Reasonably good...
Fear appeals are what you're talking about Brah. I read a lot of research in my undergrad health psych class. If I remember correctly its not necessarily showing the consequences that increase use...
Edit- spent many thousands of dollars in the store and have been a loyal customer since 2005. I have one fitness facility buying products full time from the store and have recommended dozens...