When you or your car make it up that road, you really will "rest and be thankful"
The "rest and be thankful" is part of the road between Arrochar and Inveraray (also known as the A83) in the West of Scotland. It is a particulary steep road hugging the north cliff of Glen Croe and was built following the Jacobite Rebellion of 1745-46 by General Wade and General Caulfield with the original intention of making the region more easily controllable for government forces and pacify the highlands.
This had the additional benefit of opening up the craggy west coast of Scotland up for tourists and even today it is the principal route for scottish Citylink busses to connect Glasgow with Inveraray, Lochgilphead and the Kintyre Peninsula.
The steep road will take you up to 860 ft above sea level, where it is ususally pretty foggy and damp, a micro climate generated by Ben Arthur and Ben Donich.
You get great views over the glens and Loch Fyne on the way down, and if you drive crappy 25 year old rust buckets like me, you'll always rest and be thankful when you made it up the pass.
Nae bloody bother!