I had a piece of legacy, proprietary software that communicated to another machine by wvdial over an SSH TTY (?!). It inexplicably stopped working when migrated to a newer machine, but.... worked just fine while running under strace. It appeared to be some kind of timing/race condition brought on by the new machine being faster to bring up a connection. strace slowed it down JUST enough to work.

So naturally, it now runs strace >/dev/null in production, probably to this day.