I only own one custom, and have not used it very much at all...so I'm not sure I'll have the most informed reply.
My analogy to production vs. custom knives is like the difference between going to eat a buger from a fast food place, or going to a friends to have a BBQ. When you get one from a fast food place, they are mediocre, mass produced, and you can only get it in a few variations. When you go and BBQ some burgers at a friends place, he will ask you if you like your bugers thick/thin, rare/med/well, cheese/no cheese, etc...you get the burger exactly how you want it.
In either case, a buger will curb you appetite, just like a knife will cut something. But a homemade BBQ buger, just like a custom knife puts a smile on your face and is much more enjoyable overall.
I could take the analogy much further but I think you get the point. Although many custom knifemakers create their knives to be used, if I'm really going to beat up on a knife, I'll probably use on of my cheaper more expendable knives. Right now I wouldn't want to "abuse" my custom. Maybe I'm just not ready to totally appreciate my custom knife...perhaps if I wasn't so worried about it I would use it more.
Sorry for the rambling,
Mitch