New to this.. found 4 versions of the same track already (Higher Ground)

Hi, thought I'd sign up as searches often seem to lead here.
Was just interested in noticing different masters of things sounding different, I thought it was some niche thing but in 5 minutes I've already confused myself by finding 4 versions of RHCP - Higher Ground, each sounding very different. Is this sort of thing normal??
Decided to give this song a look up as my speakers seemed to really not like it, at least the CD version I have anyway. So I turned to spotify to see what other versions were on there.

Just from the intros I could immediately tell the differences in volume and the position of the bass. My cd rip and the "2003 remaster" on spotify sound equally bad/loud, but the instruments are positioned differently.
The Greatest Hits version sound better and the What Hits version better still.

This has confused me greatly. Should I get used to this sort of thing?

Thnks, Olie