I was of course only talking about developed countries ;)
Really, afaik in europe and for sure in germany this is totally easy. It is not equally easy to reverse a transaction you started yourself. But when another person has you account-number and the public data belonging to this, all he can do is a "lastschrift" (direct debit), which is easily reverseable.
No need to downvote me. The USA is different than europe, and in this regards way behind.