Too often I see user-facing text that includes far more detail than is necessary. My current example is this web app where I can upload files for my expense reports. The help screen tells me:

You can attach the following types of files:
  • Portable Document Format (.pdf)
  • Joint Photographic Experts Group (.jpg or .jpeg)
  • Graphic Interchange Format (.gif)
  • Tagged Image Format (.tif)
  • Windows OS/2 Bitmap Graphics (.bmp)

Why why why do they bother giving those unnecessary explanations of what the file extensions mean? What they really mean is:

You can attach .pdf, .jpg or .jpeg, .gif, .tif and .bmp files.

Has anyone ever said "Hey, Bob, can you send me that Joint Photographic Experts Group file?" No? Then why do you think that people want to read it?