Keep your facial expressions as neutral as possible. If you say, "Oh, that's mildly fascinating," you won't appear disinterested with raised brows, wide eyes, and a gaping mouth. The best way to show indifference is with your body language. Keep your arms by your side at all times, even when you're not interacting with anyone. Avoid crossing your arms or holding your hands in front of you unless that's what people do in your country. Fidgeting also shows lack of interest; if you need to take out your boredom by tapping your foot, then do it! Indifference is important in some situations, such as when talking to a stranger in a queue. They might think you're rude if you display emotion early on, so hold back until they ask you about your family, friends, or work. Then you can share any information you have to offer without appearing too interested or too distracted.