Bad documentation. The worst documentation is the documentation that looks professional and complete . . . and lies through its teeth. And the support staff at $VENDOR is just reading the same documentation that you are trying to decode, and it takes weeks to get a round-trip through their ticket system.

Once I submitted an issue with a workaround that had some rather nasty side-effects, and asked for a better solution. Weeks went by. They were promising a code sample. More weeks, more "Well, we're still working on this." The solution I got back, about a month later, was exactly the workaround I'd included in the support request, with some of the serial numbers filed off.

One issue took months to resolve. We finally told $VENDOR "Look, we've got to ship. But we can't if we can't get this (critical component) working, and we'll be forced to ditch you." That got all kinds of political bullshit out of the way, and in an hour we were talking to the guy who had designed the circuit we were having trouble with.

"Oh," he said, "You have to do (three simple steps)". And I tried it while one of my cow-orkers kept him on the phone, and it worked.

I never want to deal with $VENDOR again.