What feels like quite a long time ago, when I moved from the banks of the River Lochy and the waters I grew up fishing around Ardnamurchan to the banks of the River Don, the majority of my armoury were 'loch style' patterns. But, as an avid reader of books and various fishing magazines (and a keen fly tyer
) I carried many boxes of flies that had come from the pages of Trout Fisherman, Trout & Salmon and the short-lived Salmon, Trout and Sea-Trout for those 'just in case' moments. But none of my boxes were really geared up for river fishing for trout as, by and large, river fishing where I grew up was for Sea Trout and maybe a Salmon.
When I moved to Strathdon I was fortunate to have many miles of the Don to play on, so I quickly adapted to the river and had success with some 'loch' patterns but, as Mike says, I had learnt a long time ago that if a fly looked right, fished how you wanted it to for the conditions then you'd always fish it with confidence. There has to be some sense applied, but I'd suggest that it's a reasonable axiom to state that confidence and accuracy over pattern is a key for much of fly fishing.
I do know this, that experience in fishing rivers for trout broadened my thoughts on how to approach and what to fish on a loch - in particular the use of dry flies. But that's another story.
H