Flatpak Vs Snap vs Native Packages

So I know my way around Linux pretty well. However I never really got the gist of the difference between Snap, Flatpak and Native packages.

What exactly sets them apart?

Why does everyone seem to hate snap?

I have been using all of them, simultaneously on the same system and never really noticed a difference in the way installation, updates etc are handled (syntax ofc).

I hear snap sandboxes? Is that the main reason? Thanks for your insights..