I went to Italy for the first time and left with 5 big regrets

With three destinations to visit in six days, my trip to Italy felt like a race. It started with a two-night stay in Venice, and before I knew it, I was off to Rome. Roughly 48 hours later, I was on the train to Milan, where I spent just one night before hopping on a train to another European city.

Traveling too quickly made me feel like I was always rushing. Going all the way to Milan for a single night didn't satisfy me. If I had selected just one destination, I would have been more present during my trip — and more environmentally conscious.

Justin Francis, cofounder of the UK-based sustainable vacation company Responsible Travel, previously told Business Insider that longer stays are better for the planet than quick visits.

"Fewer but longer trips mean fewer air miles, more money in local hands, and you'll have a more relaxing trip, too," Francis said.

Traveling to Europe in the summer doesn't seem like a good idea. During peak season, the continent's hottest destinations are overwhelmed with tourists.

So I thought booking my trip in October, during shoulder season (the time between peak and off-seasons) would help me avoid long lines and obstructed views.

Well, I was wrong. In Venice and Rome, I shuffled down cobblestone streets with pedestrian traffic jams. I dragged my feet over tourist-packed bridges. I viewed ancient sites like the Colosseum through the phone screens of people standing in front of me.

It seems the word is out about shoulder season. So next time I go to Italy, I'll take a winter trip.

Spending three nights in a castle for $360 was an offer I couldn't pass up. After all, it was a unique opportunity to sleep like a queen in the tower of Castello di Roncade, which was only a half-hour drive from Venice.

Though my stay was marvelous and a steal for the price point, I felt regret after learning that daytrippers can worsen overtourism in places like Venice by adding to the crowds without spending on accommodations. By not spending the night in the city itself, I wasn't contributing as much as I could have to the local economy.

When it comes to tourism etiquette, I was wrong to assume my own sense of common courtesy would serve me well.

After a walking tour in Venice, I hoped to sit down for lunch, but all the restaurants I passed were packed. Hungry and hot, I eventually cut my losses and stood in line for gelato before sitting on a shaded step to enjoy it.

As I was about to take my first bite, the nearby authorities waved their hands up and down at me — a gesture I could only take to mean "get up."

And there I was, committing an etiquette violation that, according to the City of Venice, may result in a fine.

In Rome and Venice, I had a rigid schedule. I booked tours and planned every hour of my day to see as many highlights as possible. Every place I ventured to was one I'd seen repeatedly in films and on Instagram. Seeing these famous places in person was fascinating, but I felt like I was missing out on a sense of wonder.

When I got to Milan, I dropped the agenda and walked around the city in hopes of discovering something myself.

It paid off. I stumbled upon a 15th-century castle I'd never seen on social media — Castello Sforzesco. Walking through the gate, I felt like I'd stepped into a fairy tale. Brick walls and towers lush with overgrown vines surrounded me.

Exploring the grounds of this castle was more fulfilling than the gondola ride in Venice or the Colosseum tour in Rome. And I think that's because I wasn't expecting it.

Next time I go to Italy, I'll make time to find more surprises.