Vietnam
Silk lantern is worth adding because it feels like something you actually noticed while travelling through Vietnam, rather than a generic souvenir. The trick is to choose the simple, well-made version. Small craft items look better on a shelf when they are not too shiny or mass-produced. The ideal version is modestly priced, not too bulky, and good enough that you would buy it again even without the holiday memory.
Vietnam
This is exactly the sort of thing I like bringing back from Vietnam: small enough to fit in a bag, but specific enough to remind you where you bought it. Tins and sealed products are the easiest version. Fresh or chilled fish is usually not worth the hassle unless you have checked the rules. It is also the kind of thing you can talk about when someone asks what you brought back, because there is usually a little story attached to where you found it.
Vietnam
When I think of an easy, crowd-pleasing thing to bring back from Vietnam, rice paper wrappers is a good pick because it does not need much explanation when you hand it over. Grains, pasta and rice are not glamorous, but they are useful, cheap and often taste different from the UK supermarket version. I would rate it higher when it is locally made, clearly labelled and easy to use at home, and lower when it is just tourist packaging.
Vietnam
Metal drip filter used to make strong Vietnamese coffee with condensed milk.