Obviously I only speak for myself, but...
Once you've made the leap to carrying *a* knife, it slowly becomes clear how handy they are and how much you'd been 'making do' without. (There ought to be a sort of knife nut merit badge for the first time you throw down some restaurant's dismal steak-hacksaw and use your own perfectly honed pocketknife to cut your sirloin.) After that it's just a little step further to wanting to carry the 'right' knife, and then the 'collection' just sort of happens naturally, as you figure out what you like to carry under what circumstances, etc. Along the way you develop these little preferences -- an appreciation for stag antler, or a perfectly smooth pivot/lock, an elegant line along the handle, or the way carbon steel develops patina with age, whatever.
This fall I went on a motorcycle tour, and the perfect pocketknife for that was the Buck my father gave me back in college. (He always appreciated a good motorcycle ride.) When I whittle, though, it's got to be my uncle's old stockman. Out on a walk in the woods my 'just in case' knife will be my Spyderco or my big Old Timer. Out for a night on the town and it'll probably be my Swiss army knife (unintimidating, versatile, cheap and easy to replace if lost, and has a bottle opener) At the office I usually have some kind of pen knife -- today it's a plain yellow-handled Case.
A knife is a tool, sure, but there is definitely an emotional and aesthetic component as well. (After all, a piece of junk lockback from the gas station will cut open packaging -- for a while, anyway.) A knife is an implement for shaping your environment and your circumstances, right? A really nice knife is not just an item of Quality but also a tool for bringing a little more Quality into the world. For me that adds a layer of meaning and reminds me of things I think are important.
But you know, given that you already admitted to collecting other things, the simplest way to answer your question is to get yourself something like a Victorinox and carry it for a couple months. I suspect you'll 'get it'
