The worst I have ever experienced was the inside convex rear vision mirror in a 1971 Vanden Plas Princess 1300 I once owned. (They were a Morris 1100 trimmed with several ancient British walnut trees and half a dozen Friesians.) Before I had a door mirror for it, I had no idea how far away the B-Double Mack was from the back bumper. Its 1275 cc went well with twin SUs but I guess the Brits thought convex mirrors lent some sort of prestige over the ordinary Morris.....