It depends on the amount of emails the person you are writing to gets. If you write to a high status person who gets 100 emails per day, being concise is important. There are a lot of people who think they spend too much time with email and who want to spend less time on email. Let's say I was a meetup and had an interesting discussion with someone. In it he referred to a scientific paper but when you come home you have forgotten the specific paper. You could write the person: "Sorry to bother you but could you please tell me the name of the paper you spoke about yesterday? Of course only if you don't have to do this, if you don't find easily." You could also write: "I really enjoyed our conversation about topic X yesterday. You referred to a paper about topic X, making point Y? Can you send me the link?" The second version is more likely to received positively. The fact that you tell me you enjoyed the conversation with me is information. It's friendly. Telling me specifically what paper you want helps me. It makes it easier for me to help you because I don't have to go back and reply the conversation in my mind to find with paper you could mean. As a general rule, say sorry when you make mistake. Apologize for your mistakes. Don't say sorry when you aren't making mistakes. If you want to be nice and friendly, give the other person a compliment. Given out compliments implies that you have a status that's high enough that the other person cares about your opinion. It also validates the other person. Getting a compliment puts me in a positive mood. Reading "sorry to bother you" rather puts me in a negative mood.