Yes, the answer is yes. Sure, the placebo effect does exist, too... but not with me!
Only rarely.
I have near zero experience with buyable cables, but have manufactured hundreds of own IC, headphone, speaker and digital cables, predominantly based on magnet wire. Magnet-wire cables -- consisting of dozens or hundreds of individually isolated (laquered) wires -- sound significantly different (smoother!) than braided cables with which the electrons can jump from one strand or wire to another. I have no idea why it is so, but one theory that could apply is the skin effect (electrons tend to move on the surface of a conductor). However, there's still a lot of mystery as to sonic differences with hi-fi components -- so far nobody can clearly explain why amplifiers that measure (virtually) the same sound different. So I wouldn't be too rigorous with cables, which at first look
seem to offer no basis for sonic differences.
Of course the placebo effect plays an important part with music reproduction. But let's not reduce subjectively
perceived sonic differences to it! It would be really sad if only measured data or sonic differences verified under laboratory conditions would count as facts. Whereas people who rely on their ears, such as Stradivari and the like (as well as all the audiophile electronics developers), would count as oddballs.
Anyway, I wouldn't pay thousands of dollars (or Swiss francs, resp.) for cables. I think many of the high-end cables are insanely overpriced -- if you look what's actually inside.