One of my go-to SolidWorks modeling features is Indent. When it was first introduced, it was touted as a way to "impress" one model into another -- like putting your thumb into a hunk of wet clay.
More often, however, I use the Indent command to take one part and cut out material from an overlapping part. This is accomplished by the small "Cut" option in the Indent command. That option, "Indent as Cut," makes the command much more versatile. This is also more useful to the average SolidWorks user.
It's easier to show examples than to explain; so, I'll end the up-font commentary by saying Indent is one of the few commands I've actually added to my Features Command Manager. It's very useful as it works with multi-body parts and parts in assemblies as well.
This is the way people normally think of using the Indent command. Notice you can determine the side of the extra material by what you click on in the graphics window and the corresponding "keep/remove selection" setting in the command.
Here's an example of a "normal" Indent:
This is the result of the Indent command with the settings and model shown: 
Now, if you modify the Indent command by turning on the "Cut" option, the behavior changes. Remember, this is just calculating geometry so it doesn't matter if the parts are shelled or not:
So you can see the results of the Indent command with the Cut option turned on. Think of the time savings for all kinds of models -- I see a lot of people copying sketches or making their own offset sketch geometry to achive associative holes and cutouts for other bodies or parts. Indent with Cut does it for you much faster, easier, and more robustly!

If you have an open part (think tube or hollow shaft) the regular Indent command works to build material around the end:

But if you use the Indent with the Cut option turned on, you get a hole! Note that the center core will also be there as an extra body, which is sometimes useful but more often than not you'll just suppress or delete it.

The Indent command is one of the most useful features in my SolidWorks toolkit, yet I almost never see it used. It's not just for consumer product designers -- it's for packaging design, case goods and furniture, tool design, and machine design. It can do lots of jobs better than older 3D tools and sketch-based methods, yet is seems people just don't know about it. So please share this article and spread the word: "You should use the Indent command for that!"