I love it when an image comes in focus in the oculars or appears on screen. Seeing the small world is a wondrous thing.
Of course, the thing that makes microscopy so fantastic is also what can make it exceptionally frustrating. When you're prepping a sample, often times, you can barely see it. You might know it's there because it's encased in paraffin or a block of frozen medium and you can make out the small, differently colored region. You might be able to see it floating around as it's suspended in glycerol and, again, appears as a slightly darker smudge in a tiny tube. A lot of times you can't see the sample at all. So you prep the sample as best you can and hold your breath as you wait for a signal on the scope.
And sometimes, while you're preparing a sample... it goes missing.
You saw it. It was tiny and barely visible but it was definitely there. And then, as you're transferring it from its tube to a sample holder... it disappears. IT WAS JUST THERE. YOU JUST HAD IT. You put every tube and instrument and your hands under the dissecting scope but don't (can't?) see it.
Samples don't work for all kinds of reasons, the staining didn't work, the tissue slice folded over as you put it on the slide, your hand twitches and super sharp forceps take a hunk out, the bacterial concentration wasn't high enough in solution, the flurorphore got left out too long and bleached, the fish didn't get enough anesthesia and is wriggling all over the place... But it's really exasperating when you lose it and can't find it again!