I know mine used to. I didn’t organize my thoughts, I was too wordy, there wasn’t enough white space. Sometimes my “ask” wasn’t clear. When your emails suck, it lowers your productivity, because people have to come back to you and ask questions about your email. You know what else? It can negatively affect how people perceive you. They may not consciously think “Her emails suck,” but they just feel like you aren’t very focused or clear.