I absolutely love this song and this singer, though truthfully I prefer the non-acoustic version (couldn't find the original on YouTube, but look it up on Amazon or iTunes if you're interested).
The song is originally by Bob Dylan, and while his version is, of course, awesome, I prefer Mike Ness's because of the heightened emotion behind the song's message.
The song is about a breakup in which the couple just doesn't really mesh anymore and probably never really meshed, but I find that it makes a lot of sense to me in a different sense. I've gone through some stressful times lately, both personally and in my work, and this song always reminds me to let go of the people/situations that are toxic to you and move forward with your life as only you know how to live it. Seriously, on bad days I listen to this song 7 or 8 times.
In fact, this song has been so pertinent to me over the last few months that I'm considering getting a tattoo in honor of it. Just haven't hammered down a design yet. My husband also performed this song for me at our wedding, despite the fact that it's a breakup song, just because he knows I love it so much.