Files with No Extension

What’s up with people sending files with no extension? At least once a week someone sends me a file without an extension. Sometimes I can fix it by adding an .rtf or .doc extension. Sometimes I can’t.

How do people manage to send files without extensions? How do they lose the file extension by sending it as an attachment? And if the file somewhere along the line loses its extension, why wouldn’t they fix it before they send it off?

It’s annoying.

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