The best thing you bring home from a trip is usually small, used, and slightly specific to the place. The worst is a bag of objects you bought because the shop was there. A few rules keep the suitcase honest.
Buy what you will use in ordinary life
Food you will eat next week, a tea towel you will actually dry dishes with, a book you will read on the train home. These survive the return. A decorative bowl that only makes sense on holiday becomes clutter by Tuesday. If you cannot picture it in your kitchen or your hands a month from now, leave it on the shelf.
One thing from a person, not a chain
A jar from a market, a print from a shop you wandered into, a pencil from a stationer. You remember who sold it. A branded bag from the airport is a receipt. Spend the money once, on the thing you noticed, rather than three times on things you were nudged toward.
Weight and regret
If it is heavy, breakable, or a size you are guessing for someone else, it is probably a no. Clothes you try on in the place are fair. Clothes you buy for a version of yourself that only exists on holiday are how suitcases get sad. Bring home less than you could. The trip is not a shopping list, and the empty space in the bag is part of travelling well.