It gets even more interesting: to interfere in the double slit experiment, the light has to take a longer path for some points and light is really good at finding the shortest path. And, since you can extend the double slit experiment to infinite slits with infinitely thin blockers between the slits, you can leave away the slits entirely and still have a valid version of that experiment and get interference. It's just, that most interference is destructive.

Veritasium had a very interesting video about that recently and my extrapolation of this is that there is neither a collapse of wave functions nor multiple parallel universes.

My intuition says that the wave function is there after being "observed". There is no multiple possible outcomes, just very visible ones and a lot of destructive interfered ones.

However what i just wrote is not science but me extrapolating from science so don't take it for anything more than that. It somehow causes quantum physics to make intuitive sense for me so i like it. Nothing more than that.