I started this list when I couldn't get over how many times I saw the phrase, "floats like a cork" refering to various fly types. If someone is adamant about something, it's a good indication that there is a problem in that area. Some of them I still struggle with, some of them I used to have a problem with, and some of them I just made up. These are meant to be humorous, and if you have any to add, please do so.

Floats like a cork: sinks on the third cast

CDC-emerger: a fly that sinks like a nymph, but that is fished without a strike indicator

False-casting: a technique to dry a fly that ends when you give up and decide to fish your fly wet, or when you get your fly tangled in a tree

High-floating tip: the end of a fly line which sinks immediately after landing on water, making a splash-and-go cast impossible

Splash-and-go: that magic moment in a dynamic roll cast between tangling your fly in the weeds behind you and not having enough casting energy to unstick your fly from the water

High-visibility fly: invisible from 25 feet

Strike indicator: a device used to spook fish. When added to your leader above a nymph, it will slowly sink until out of sight.

Fish your fly near the bottom: perform a physical impossibility

Use 1 1/2 times the water depth as your indicator setting: leave your nymph on an unseen snag on the first cast

Fish a log jam: dump your fly box into the river to save time tying knots, then breaking them off

Cast a Clouser minnow: use a spinning rod to avoid bruising the back of your head

Surface-feeding fish: something you likely would have seen, if you had been here last week

Small creek: a body of water so overgrown that you cannot possibly make a cast through the brush

Large river: any flowing body of water bigger than a small creek. It is characterized by having the best fishing water on the opposite bank from your location, which is out of casting range.

Stack hair: make a series of loud noises that wakes the baby up, makes your wife yell at you, and leaves hair all over the kitchen floor

A 'bunch': a quantity of deer hair that either means "the right amount, but not too much" or "more than you can handle at one time". You can't tell which until it's too late.

Apply dubbing: using too much material that fails to stick to your thread

Up-riding hook point: a fly tied in such a way that it gets stuck on the bottom anyway

Weedgaurd: a piece of monofilament added to a fly to prevent light striking fish from getting hooked, but is completely ineffective at avoiding fouling in aquatic vegetation