So take a quantum system, for example an unstable particle, that will soon decay. Keep observing this particle as frequently as possible.
(It is not possible to observe it infinitely frequently, so time evolution can't be 100% stopped, this can only be approached. Neither is it really known what "observe" means here, but a measuring device or an adult human seems to do the trick. Whether or not this is completely true is not the point here.)
So we keep observing the particle that will soon decay. And it never decays, because we have "frozen it in time" (arrested it's time evolution). Or at least we slowed it down to an almost complete halt.
Depending on the frequency of observation, we can also speed it up in time, so the decay will likely happen faster than it should.
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Time is already a difficult thing to think about in several ways, so I thought why not make it even more confusing.
So for example one could wonder, when we suddenly stare at an analog watch, does the seconds dial sometimes really stop for a moment, or is our mind simply playing a trick on us?