• An easy out with persistent sellers: (for example, "Oh, I can't buy that without consulting my husband, but he's back at the hotel. Maybe we'll come back later").
• An excuse not to join an activity that you don't want to do; "Sorry, my friend is waiting for me at the hotel; I have to get back!"
If you want to go even further, embellish the story by picking up two room keys when you check in (you never know who might be watching).
What you learn by travelling alone
Travelling solo can be exhilarating, lonely, enlightening, an adventure, and tough all at the same time. Nonetheless, it will teach you so much about yourself. Such as:
1. How to be self-sufficient
When you're travelling with a group or a partner, it's easy to sit back and let someone else take charge. Bad at math? Someone else can figure out the exchange rate. Lacking in language skills? Your friend will find out where "les toilettes" are.
When it's just you, you don't have anyone else to rely on, so you're forced to figure out directions, get yourself to the airport on time, and calculate how much to pay. Doing all of this on your own will give you new skills and a sense of independence that will carry over to your everyday life.
2. What you really want to do
Travelling with other people means compromise - which isn't always a bad thing. Having to take into consideration someone else's interests and needs can open you up to discovering places you never would have gone on your own.
But when it's just you, you can take time and decide exactly what it is you want to do, and at what pace you want to do it. Maybe you want to find an obscure museum that only people with very specific hobbies would find interesting.
Or maybe you want to toss out your schedule for the day and just sit at a cafe watching the world go by. When it's just you, you don't have to think about pleasing anyone besides yourself.
3. Who you are when no one's watching
When you're alone in a new place, no one knows who you are, so you can be anyone you want. Maybe you're shy when you travel with your more outgoing friend. Or you're less adventurous when you're vacationing with a reserved companion. Being by yourself in a new place means that no one has any preconceived notions about you, so you can take on any personality you want.
4. How to be comfortable in your own company
Being happy spending time with just yourself is a very valuable skill. When you're vacationing solo, you'll have lots of one-on-one time with yourself. Learning how to be okay dining as a party of one, visiting museums alone, and so on will make you a much more confident and interesting person in the long run.
5. How to make friends
When you're by yourself, you're much more open to meeting new people. Whether it's a brief chat with the local next to you at the coffee shop, or inviting some new friends from your hostel to go out with you at night, going independently can make you much more receptive to new people and situations.