VPN: Good or Bad?

I know what you may be thinking and that is how can a VPN be bad. It gives you straight connection to where you want. security! that makes people happy. it makes me happy to, but when my sales guy goes out and sales a AD structure to a small company to use a VPN it sucks...nothing but headaches! The biggest issue is I'm not building it from scratch...I have to use exsisting aweful peer-to-peer network and make it connect (useing a VPN) to my server with the AD... Sure not a problem. I did this...I created the VPN and connected it and everything was working fine. That is until they lost their connection to the internet. DOH! So I huffed it all the way back to my Server room (Yes I ran...Good thing I quit smoking or it would have been worse then it was) and unplug the vpn, disable the software connection and then reprogram the VPN the other way. (swap the server and client VPN ends) Now I'm writing staic routes and reconfiguring this whole thing and I'm a Windows Server Engineer...Not a router programmer... I dislike to program, I like to build and maintain servers. But due to the wonderful world that I live in I get to do it all. This isn't a big issue for me, just cause I don't like to do it doesn't mean I don't know how. I also know how to farm, but you will not see me doing that.
Anyway back to the VPN... So all in all it's not done yet, this week is the deadline and I'm under pressure cause I don't have enought time in the day to do my work, plus the remaining work out there. But, some of my best work comes from being under the gun so here I go!!

OK now that I got that out I feel better and focused.

EDIT:
You know after I posted it I realized I didn't say if they are bad or good. The answer is both.
Bad = when used to connect an office that uses the same internet but is seperate companies to a server, but only connecting one of the companies.
Good = In any other situation.