Some things are just too easy. One of the most productive fly patterns I've fished is the Zebra Midge, but it is also my least favorite nymph. Why? Because it's too easy. Too easy to tie and too simple for my taste. Yes, I admit it's the spitting image of a midge pupa. But I just feel like I'm cheating when I pull a fish out from a deep pocket with a tiny zebra in it's lip.
Add more stuff to the zebra midge chassis! If you tie a tiny wing of white deer hair below the head of the fly you have a serendipity.
A famous Montana version of the fly is the $3 Dip from Blue Ribbon Flies.
Here is a fine tying video of the $3 Dip from Tight Lines (Video)
The original is tied with white deer hair which gives a nice look, but I have found that it is not very durable. After you catch three or four fish on the serendipity the deer hairs will break off and you are left with...the dreaded zebra midge (which will continue to catch more fish).
To make a more durable fly I tie the "EP Dip" using Enrico Puglisi or Widow's Web fibers instead of deer hair. They are much more durable and stay put with a single drop of zap a gap applied to the thread wraps.
I imagine that the trout think that a serendipity could be a midge or a tiny baetis because of the wing. But more likely they just think it's a zebra midge that needs a shave.