I started buying Nikon prime lenses for the wider angles to go with my AF 20mm to 35mm, AF 28mm to 200mm, and AF 28mm to 300mm lenses. First I bought the 28mm PC lens, then a 20mm AF lens, a 24mm AF lens and a 50mm AF lens. Somehow I have extra 50mm lenses, both AF and MF. This is so upsetting I am going to buy some more lenses.
I know this feeling. I have some fifteen or so 50mm-ish lenses, of various mounts, and I'm on the verge of acquiring a Zeiss 50mm Planar (Leica mount) for, shall we say, unspeakable purposes.
The surplus of standard lenses is a well known phenomenon.
The moment one acquires multiple bodies for parallel use with different focal lengths (or just for reduncy) the typically at the bodies hanging standard lenses form a surplus.