Beyond the obvious, the difference is that there is often a real stigma attached to depression, resulting in a serious reluctance to recognize it, talk about it and to seek treatment that might hold it in check. On the other hand, "Fuck it" seems to have worked its way into our everyday vocabulary with its application in daily dialogue, books, movies, etc.
Over the past dozen years or so, lots of previously taboo topics have managed their way out of the proverbial closet: LGBTQ, cancer, Viagra, female libido, pedophilia, weight, race, gender specific sex issues, religion, etc.
What differentiates depression—along with some of the above—is its "invisibility". It is very personal nature, and nobody knows you are dealing with it unless you tell them or you are in such a serious decline that it's obvious. This makes the support of friends and family all the more important.
People I barely knew have talked to me about their cancer and other issues that were less than obvious to an observer. So, as I said, "Fuck it", we all need to work to allow people with depression to deal with it openly. Maybe we stop refer to it as depression; maybe we start referring to it as "burnout" or a "chemical imbalance". Depression by any other name is still depression, but let's start referring to it in ways that can make the sufferer feel most comfortable, eliminating the stigma.