Having worked at a Harley Dealership as a Service Writer last year, I can assure you there are guys out there that can not install their own battery or tighten battery clamps without breaking something. Amazing huh!!
One of the funniest threads I have read in the past year was a guy who was going to do something major (I can't remember what for sure) but he was asking how to get the plastic tray off the battery. He couldn't figure it out.
I thought, man if you can't do that, what makes you think you could do something major. lol