> I pass three speed bumps on my street. I'm driving at low speed [...] I don't even brake before them
That's a lot of "I"s for something so many other drivers in the world have to drive across, in many, many different designs. Bumps, "nipples", cushions, tables, bars, made from rubber, asphalt, cobble stone, metal, with different ratios between height and width, different profiles, etc.
But it also depends on the car, doesn't it? Some suspensions are harder, some cars are lower, this creates discomfort or damage. Sometimes they have to rev the engine to cross over at very low speed. Not to mention larger and heavier cars like vans or garbage trucks which also damage the bump on top of everything else. Sometimes even cyclists have to put their butt on the line. The Wikipedia page would have put your personal experience in context [1]. Speed bumps are the cheap for the city but there are compromises.
Many countries with well thought out traffic use bumps where safety is paramount, like raised pedestrian crossings (table). The rest of the speed limiting effect is achieved with smart road design wherever possible.
[1] https://en.wikipedia.org/wiki/Speed_bump#Disadvantages