Always remember just how few people have as deep an understanding about all of the things they own. I could go on for hours about my Beatles collection, about the variances in labels for VJ releases in 1963/4, or what take of "For No One" appears on Revolver in mono, stereo, and all subsequent re-releases, you'd be impressed.
But I own 3 BMW's, all of which I'm told are special German high-performance cars capable of incredible feats of automotive excellence on and off the track, yet all I use them for is driving the kids to soccer and commuting to work in traffic. When I look at my position, my lifestyle, and my net worth the BMW brand seems to be exactly what I should be owning and driving and that's all it has to be. Reliable, attractive, safe, expensive. Whatever else is going on under the hood doesn't matter.
There is no lesson in this. Your girlfriend's Rolex man just wants a nice watch. Maybe he's the world's foremost expert on 1920's postage stamps. Or, perhaps, like most successful people who can be so cavalier as to drop $6,000 on a wristwatch he is so good at his job and so focused on doing it that he doesn't have the time or energy to become an aficionado of all of the trinkets he accumulates in his life. It's a piece of jewelry, after all.