However some people apparently manage to work at jobs for years without making any friends. This is a useful piece of information to know before hiring them.

Still, if you come to hire, always follow up the references. Always.

If they lie about anything on their resume my company walks away. The last guy I interviewed we talked for my alloted time and it was clear he wasn't quite up to par but I wanted to know how much he knew. The next guy after me sent him home within minutes because there were flat out lies on his resume.

One may not imply the other (lies !== bad employee) but it's a red flag.