Not quite wasting my time. I'd try to behave the way I try to even if there wasn't a God who told me to, because that's the decent thing to do (and that, in turn, can be argued from a sociological point of view as well as a theological one).
In case there is no God, there's not really any harm done -- I just got some of my spiritual solace from self-adopted delusions. Still, it worked.
In case there is a God, things should also work all right. Of course, if the real God does not like my semi-flippant attitude towards faith, I'm in trouble -- but would that kind of God be someone with whom I'd want to spend the rest of eternity anyway?
The fact that I chose the Lutheran outward forms is a matter of upbringing. Ultimately, they work for me; but this is not too different from the way I've adopted certain theoretical frameworks for my day job. They, too, work for me, but at the same time I recognise that some competing theories work for others.
Nfr