I have seen (ad hoc) implementations go quite bad many times. I encounter them quite a bit as a distributed replacement for some type of db transaction where th

I have seen (ad hoc) implementations go quite bad many times. I encounter them quite a bit as a distributed replacement for some type of db transaction where the db is something like rds; someone thought to be smart and write 'things at scale' (they read on reddit etc) while a db transaction would've been the correct solution and they didn't need scale anyway (or underestimated the current db capabilities for mysql/postgres).