Stopped at a marine reserve to try to see some giant clams. Failed to see any clams. Turns out I didn't swim far enough. I was looking in the wrong place, growing frustrated with my leaking goggles and the cloudy water.

I gave up and returned to shore, resigned to not seeing whatever it was I was supposed to see, telling myself that my entry fee would support the local community, too stubborn to ask for guidance. I was deflated and red under the late afternoon sun.

Other people we were with did manage to see the clams. Their goggles didn't leak. They went further than the rusty shallows peppered with fishing gear and brickwork, drifted beyond what I'd thought were boundary nets but actually turned out to be the start of the main reserve, and came back with the glistening look of tourists who had just experienced something worth experiencing.

Apparently you couldn't mistake those clams once they came into view. They were vast and fluorescent. They change colour depending on your angle of approach and your proximity. They sound celestial and bizarre. I don't doubt that, had I seen them with my own eyes, they would have left a lasting impression on me.

I've considered returning to the same spot and trying again, but there's something about 'not seeing' that might be worth preserving.

A similar failure to see what I'd come to see happened in Sicily the year prior. In Agrigento, we walked around the Valle dei Templi, one pair in a huge tourist pond, and though we were impressed by the toppled columns, the encroachment of native trees, the views of the living city on the hill and the Mediterranean flat, blue and far beyond, we couldn't help but feel the ancient buildings themselves failed to match the numerous postcards we'd seen of the site, postcards that are inescapable for anyone passing through the region.

At a restaurant afterwards, we realised we'd somehow circumnavigated the main temple, the best-preserved, the mightiest of all those structures, the one that draws the crowds. Perhaps we didn't walk far enough, failed to get beyond the shallows, underwhelmed because our gaze didn't point in the right direction.

Chances are, we'll never be there again. The probability of returning to the exact same part of the world, any part that isn't home, is often low. What's unseen usually remains unseen.

A life riddled with things that you miss. A tumble of magic stones in a clearing you never stumble upon, giant beings obscured by fogged glass under the sea, discontinued exhibitions of dead or dying painters, museums shuttered by public holidays, walks eclipsed by hangovers, a vista never glimpsed from the car window because you were talking to the passenger beside you, or decided to rest your eyes for a moment, rendered sleepy by the passing road. Moments that happen somewhere else, or at a different time, to different people, in different gardens.

Of course, each missed moment is supplanted by the moment that does arrive, the ever-recurring moment, there unbidden, hopelessly refreshed. Failing to see something, despite how it may feel, never leaves a true vacancy. Gaps in experience are never really there. We can not help but fill them, like tidal pools, their wriggling contents carried to and fro, overspilling the boundaries, day after misremembered day.