Chance would be a fine thing.
Chance is bombing through a pine forest on a bit of singletrack barely wider than you are, with handlebars scraping the edge of the trees, with the 'surface' being a mixture of wet rocks, roots and occasional hub-deep mulch, all coated in unimaginable slipperly filth. Where the slightest touch of the back brake instantly locks the back wheel and drags half the forest floor down the trail under the back tyre, it's knobs barely any use.
Suddenly dealing with wet tarmac on a road bike doesn't seem so bad ;-)
Seriously, though, in my experience far too many people out there have an irrational fear of the front brake. There's very few on-road situations in which it's going to be a problem and those that are are obvious - wet leaves, ice, loose gravel patches etc. If you're happy to lean over in a corner on 23mm of rubber there shouldn't be an issue with braking on it. More to the point, as Sheldon notes the quickest way to stop a bike is the front brake alone in most situations, so if you can't commit to it you'll be in trouble should you ever need to emergency stop.
Edit: You've expanded on your enigmatic statement since I was typing....I can see where you're coming from, and I certainly check my back brake is always working, but the danger with using it all the time is you are braking sub-optimally in most conditions. It's not a problem until, say, you begin braking with both and then have to emergency stop, in which case you need to manage both wheels, and brace, and deal with the fact that when you're front is at max the back is going to lock. In other words you've de-trained yourself from using the front brake in an attempt to avoid de-training yourself from using the back.