[sgarland]

A couple of examples I've found:

Celery spawns n workers, defaulting to the number of logical processors available. As anyone familiar with cgroups can tell you, this is fraught with problems when containerized, since nearly all mechanisms to detect processor count (or available memory) lead back to `/proc`, which will dutifully report the host's information out to the container. This leads to questions like, "I requested 4 vCPUs; why do I have 4+n threads?"

ORM in general. The worst example I've seen was querying a massive table, and to get n results from the end, was using OFFSET + LIMIT. It was also deliberately not using the PKEY, leading to a full table scan every time the query ran. If you aren't familiar with DBs, it may seem perfectly reasonable that querying a ~100 million row DB would take a long time, when in fact it could and should be extremely fast with a properly written query.