I was done with OSM within a few days. I fixed some streams to be in the right place, reverted.
This post box is no longer there. "I'll drive round and check", "no need I'm stood there, it has gone". "I'll drive round tomorrow"...I got the impression i was on someone else's patch and gave up
I had the opposite expeirence just a few years back adding a air gun club. I used some layer and someone else fixed it up for me.
To get instant pushback from other mappers is fairly unusual; I would say you had bad luck (or live in Lithuania). In a lot of the world, edits correct or incorrect can take months or years to be noticed by another mapper.
But with regard to bodies of water, there are systems that monitor OSM and warn if someone has tried to "move them to the right place". These details were often added to OSM from professionally surveyed maps, so they are in the right place. However, ordinary people's consumer GPS is typically a few meters off, and they end up moving things to the inaccurate coordinates on their screens.