I only brought a few things with me when I went to Europe (although people who saw me try to lift my backpack onto the luggage rack in a train may disagree.) Of what I brought with me, some things weren't really necessary (sleeping bag, water bottle, etc.) and one thing was unexpectedly useful. A good friend gave me a packable shopping tote for my birthday- one of those bags that scrunches down into a little pocket. It was great for traveling... I used it at grocery stores, when in transit (it was a much bigger, better carry-on than my smaller purse), and for going to the beach. When I didn't need it, I just smashed it into my backpack. So, next time you go on a trip consider bringing one of these simple bags along with you.