Hawaii volcanism is what geologists seem to call "nice and friendly" - low viscosity lava, not prone to explosive eruptions (unlike the stratovolcanoes of the Andes or the Pacific rim in general) - this is because it's caused by hotspot volcanism in Hawaii.
It’s not nice and friendly because of the hotspot volcanism.
It’s because the hotspot has a chemical composition that is generally low in dissolved gasses and very liquid/flows well. (Lots of silicates I think?)
It tends to come out nicely and stay liquid as it leaves, so vents don’t plug up. Also, because of the relatively low dissolved gasses, pressure doesn’t spike as high when it’s flowing out of the chamber like many other magmas do, causing explosions.
Hawaii exists basically because it’s great for building up islands/mountains without blowing them up as part of the process.