Far from intuitive (Word 2013)

Be aware that you are not talking to Microsoft here. Almost everyone in this forum is a volunteer, just another user trying to help. Even the Support Engineers are not Microsoft employees; they are employed by an outsourcing firm engaged by Microsoft. It is extremely rare for any Microsoft employee who is actually involved in the design of the Word application to participate in this forum.

As for the spacing, in Word 2007 and 2010, the default paragraph spacing is 1.15 lines, and the default Spacing After is 10 points; apparently in Word 2013 this has been reduced to 1.08 lines and 8 points. If you don't like this spacing, there are several ways to change it.

1. At the most basic, you can apply the No Spacing style (the second pane in the default Quick Styles gallery). This will apply to the current paragraph or selected text.
2. On the Design tab, in the Document Formatting group, for Paragraph Spacing, you can select No Paragraph Space. This will change the formatting of the Normal style and will consequently apply to all paragraphs in that style.
3. Both of these quick-and-dirty changes affect only the current document. If you want to make a change that will affect all new documents, display the Styles pane (Alt+Ctrl+Shift+S) and the Manage Styles button in the bottom left corner. In the Manage Styles dialog, select the Set Defaults tab. Change the line spacing as desired and select the radio button for "New documents based on this template," then click OK.
4. Alternatively, right-click in a Normal paragraph in your document, choose Paragraph, change the settings as desired, click Set As Default, choose the radio button for "All documents based on the Normal.dotm template," and click OK.

If you use option 3 or 4, be sure to say Yes if prompted to save the Normal template when you quit Word.