I also get that feeling. While logically I know it almost certainly is not true, I get that "feeling" nevertheless. Still, no denying what one "feels," it's probably like those optical illusions, where you know the line is straight, but your mind says it is curved.

However, there may be some small truth in the case of air-cooled motorcycle engines. With those, you get to hear a lot of the internal sounds, and often air-cooled high RPM engines lose more viscosity than typical water-cooled lower RPM automobile engines. Even more so when you consider most motorcycles share engine oil with the transmission gears. So you are essentially, in many cases, putting a thicker oil into the motorcycle engine when you change oil (and transmission in most cases, since most MC engines share engine and transmission oil). This can quiet the engine and tranny a bit, e.g., gear rattle in neutral, etc.

Years ago, Golden Spectrol brand MC oil played this game a bit by formulation their oils to be on the very thick end of the SAE viscosity ranges, and then getting testimonials from MC riders about how much better their engine/transmission sounded when they used GS oil.

But, as Ard said, it is mostly, if not all, in my/your head.