Sometimes I just laugh reading the advice Googlers have to give webmasters.
Case in point: Google's John Mueller responds to a thread in the Google Webmaster Help forums about properly how to use hidden content and not get in trouble with Google. Truth is, there are legitimate reasons to do it for design, and Matt Cutts discussed it back in July 2013. But the way John replied was awesome.
Here it is:
I'd recommend not using hidden text to hide keywords on a page. If something is relevant to the page, then it's probably relevant to the user too, so I'd recommend showing it to the user.
If the content is relevant to the page, then it is probably relevant to the user also - so show it to the user, don't hide it!
The simplicity of the answer makes you want to laugh out loud. Which is why using a Homer GIF on this story also makes a lot of sense.
Forum discussion at Google Webmaster Help.