What the hell?

That's a question I couldn't shake, an idea that wouldn't leave me. I wandered the now busy streets of Siem Reap just trying to take it all in, the people, the traffic, the tourists, the shops, the fact "Pub Street" was now a thoroughfare filled with traveller-friendly drinking holes, rather than just the one place in town you could actually get a beer.

I couldn't find the hostel where my brother and I stayed last time, some 12 years ago. I couldn't find the bar where we played pool and met those English girls and where my brother got lost for a few hours after jumping on the back of a scooter outside and disappearing. I couldn't find, of course, the two guys we paid to ferry us around on their scooters to the temples for a couple of days. Nothing was the way I'd left it.

Siem Reap has changed. In the last few decades it has morphed completely from a sleepy country town, a favoured stop-off for adventure travellers and the banana pancake crowd, to a mainstream tourist destination complete with international airport and five-star hotels and a cruise port, which just breaks your heart, in a way.

Or at least, it broke mine. Where was the time I used to have? Where was the place I used to have it in?

I hated Siem Reap when I first went back a few years ago. I hated that it had changed, that the world had changed, that mass tourism had arrived and swept away the dingy pub and the English girls and the horrendous sunburn we picked up on the boat ride from Phnom Penh and replaced it with something else. Something nicer. Something easier.

It took me a few days to realise my mistake, a few days of eating in new places and drinking with new friends and seeing the temples through new eyes to discover what I should have known all along.

You should never look back. As a traveller, you should never get hung up on the past. You should never be that guy telling everyone they should have been here 20 years ago. You should never chase memories. Never obsess over what was. You'll drive yourself crazy.

This is the secret, I think, to a life of successful, enjoyable travel. It's nice to have memories of past experience, but they shouldn't inform what you see or what you feel in the current moment. At the risk of sounding like one of those Instagrammers who drive me nuts, you actually do need to be present when you travel, to focus entirely on what's in front of you now, what makes it great, what makes it special.

Never look back. Never think too much about the way a destination once was. Never go back to a place expecting that you'll have the same experience again, that you'll hang out with the same people, that you'll eat the same things, and that they will make you feel the same way they did all those years ago.

That isn't to say you shouldn't return to places you've loved. On the contrary: you should. One of the greatest joys of travel is rediscovery, it's getting to know a city or a country you're already passionate about just that little bit better.

But be sure you're revisiting a place, not a memory. Be sure you're not trying to recreate a holiday from the past. Be sure you're seeking something new and exciting and fresh.

Remember, it's not only the destination that will have changed by the time you return. You will have changed too. You'll be older (definitely). You'll be wiser (maybe). You'll be more mature (possibly). You'll be more risk-averse (there's a chance).

A complete recreation of my first trip to Siem Reap some 12 years later probably would have sucked. I would have been annoyed at my disappearing sibling, rather than slightly alarmed and mostly amused. I would have felt too old in that pub full of backpackers. I would have missed having airconditioning in my room.

You do yourself no favours by looking back at your travelling past while you're still out there having new adventures. Memories are for home, when you need something to buoy you through another stifling workday. When you're travelling you should just be enjoying what you have, celebrating any differences, treating each destination like it's completely new and exciting and different.

If you don't think you can do that, I would suggest not returning at all. The world is a huge place – there's always somewhere new. Go to those new places and enjoy them through eyes that are enthusiastic and fresh.

You never want to find yourself hating somewhere you used to love, just because it's changed; just because you've changed. You never want to obsess over that question that has no answer: What the hell?