Its amazing how many of the holes mentioned are nowhere near 90 degrees turn - including #10 at St Enodoc. Much of the time these holes are closer to 45 degrees. Perhaps this about the area we all consider to be a sharp legger, because 90 degrees is really very, very sharp.
Ed
Bunkers and/or rough can define a dogleg - they most often do on links - though even 45 degree leggers are rare. I would think most of the time something is in the way that must be hit around such as the 1st on North Wales (houses), but I bet that is only about 60 degrees.
The one hole I am thinking of now is Pennard's 17th. The map shows it incredibly straight, but I am sure this is inaccurate as with the 10th. In any case, that turn is so sharp that to try and cut the leg on the second becomes very difficult because of the angle making the fairway so narrow. Effectively, one has to really go for the green on the second or hit out to the turn of the leg with a layup. So many times times I have seen what seem like good shots cutting the leg, but not going for the green lost. I don't know if I can call this a good hole, but it has always frustrated me so it must have some merit.
Ciao