How normal-sounding is the slogan "I'm lovin' it" to native ears?

I know it sounded quite odd to me when I first heard it — and it still sometimes does —, but I can't even tell why. Sure, love is supposedly a stative verb, but it's being used in progressive tense all the time without sounding weird at all (lots of songs come to mind, e.g. Loving Every Minute). It's only this particular slogan that somehow doesn't quite work for me. I would expect that to be totally on purpose — it's advertising, after all —, but Wikipedia doesn't mention any objections from native speakers (as it does with "Think Different" and "Winston tastes good like a cigarette should"). So I'm asking the native speakers of this community: does "I'm lovin' it" sound completely natural to you? Just a bit off? Completely weird? Why?