What are some of the most common issues related to VPNs?

Every week, one of the most prevalent searches on TechRepublic is for “VPN” and I have been wondering why that is. Are people having difficulties in troubleshooting VPN problems? Are IT pros looking for information on setting up and configuring VPN servers and/or VPN clients? Are they looking to compare different VPN solutions? Are they looking to set up site-to-site VPNs to replace leased lines?

I thought I would throw this out to the TechRepublic community and simply ask, “What are the most common VPN issues that you face?