From my experience being taught nav in the US I think its probably due to not being taught it completely in the first place. My navigation was taught with a complete emphasis on knowing the freeway system in Florida for navigation and forced landings.
The brits are anal retentive in the extreme with the old stopwatch drift line and all the other good stuff. But it does work.
If you do a search on the user name BEagle he has posted some extremely well written and practical posts on the subject of Navigation.
Nav is a combination of preplanning and getting yourself into some habits which you need to keep current. I would be pants these days at VFR nav without all the IFR kit to back me up.
Personally I would go and find some old hairy who has been flying since Wilbur and ask him to teach you the old way of doing it. You will learn a heap more about being a pilot as well as sorting your Nav out.
Being a pilot is just a series of habits you get into, most of them take time to bed in but after that they become subconscious and as they do the work load drops off. Just as you get happy with VFR you start instrument flying and the work load goes through the roof again. After getting your head round that the odd trip VFR is a pleasure and the workload seems to be very little.