⌘-Shift-5 to disable that floating screen shot thing... I love you. That thing is _so slow_ and distracting I always worry my screen shot didn't actually save until that slow window popped up on some random screen.

I used to hate the screenshot preview, but then discovered I could drag it into applications and websites, or into the trash if it was a mistake.

Also, with the preview in the foreground, Command-C will copy the screenshot to the clipboard (e.g., before putting it into the trash).

Or double click for some quick editing and annotation.

You can even have it automatically open on an iPad to annotate on– I cannot overstate how useful this is when you're trying to write instructions for something.