A bike would be doing something like 15 to 30 km/h depending on the type of cyclist.

Some time ago I've had a discussion about what you describe with some of my co-workers (most of us drive around 40.000km/yr for work alone). The general outcome seemed to be that people with a bit more experience (30+ of age etc) are much less likely to actually have that emotion than less experienced drivers / younger persons.

Looking at my own feelings I can honestly say I don't even think about it potentially being annoying or irritating. It's not even that I purposely think "ah, it's ok, other people have just as much right to use the road as me", it's as thoughtless and automated a thing as changing gears / lanes or letting go of the gas for a city zone.

As a 20yr old, when a lot of my driving wasn't engrained "-brain- muscle memory", it was different and I remember a couple of times I got annoyed at other drivers or "cheered" when "annoying" drivers got the short straw etc. I wonder if this is something most people tend to grow out once they get more experienced or once they "adapt" from others who have learned not to care.

Btw. I think in many situations that comment on petrol is faulty. You're at lower gear but also at lower speed. And in most cars 25-30 km/h is a pretty good "tuned speed" (gear / fuel use).