Exactly. I have a nice variety of colours when it comes to traditional garter ties (House of Cheviot) and elastic 'flashes,' (Lochcarron) but almost every time I wear kilt hose, no matter what colour they are, I choose the red garters. It's so weird...almost comical.
I do the same. Every once in a while I'll wear my charcoal grey garter ties, or think about ordering garter ties in some other colours. But then I ask myself, "Why? You'll still just end up wearing the red ones, so don't even bother." I used to think that red garter ties was too over-done by kilt-wearers, and indeed I would hate to see everybody wearing the same colour. But I have come to appreciate the accent one gets from that bit of colour in that particular location. Especially for those of us who have tartans with just a tiny bit of red (like his MacLeod tartan), though it's certainly not a requirement.