Recommended
Why it's not possible to synchronize turn signals (but also absolutely is)
Why people recommend it
A Technology Connections explainer on old thermal car indicator flashers and why their timing drifts, praised as clear and entertaining.
Watch for: covers the older bimetallic type of flasher
In their words
While all previous replies are correct, a clearer (and certainly more entertaining) explanation is this video from Technology Connections.
Daniel Melendrez on electronics.stackexchange.com, Sept 2022. CC BY-SA.
You're not the only one who is maybe (slightly) obsessed with this;-) surprisingly, someone made a video about this, see:
Bimpelrekkie on electronics.stackexchange.com, Jan 2022. CC BY-SA.