When you copy text into Microsoft Word or email from an external document, the formatting of the text usually comes across as well, particularly if your source is a web page. This requires time to go through manually and correct, and tends to be pretty annoying.

A time saving tip is to highlight the text that was pasted into Word or your email, and press Ctrl + Space at the same time, and the text will automatically be formatted to suit the rest of the style of your document.