Fallacy: Time only moves forward

[KarlEvardNYT]

This is more an implementation detail but if a clock runs fast it will occasionally need to be set back to stop if from drifting too much. If this is an automatic adjustment, it'll likely only be a few ms but if it's manual it could be several minutes. Monotonic clocks don't do this but are subject to drift. Unreliable Clocks in chapter 8 of Designing Data-Intensive Applications covers this well