That. It's nearly an enemy to an editor. When we talk, we use "that" as a transition word to help us keep our thoughts flowing while we talk. It gives us a chance to pause and think while we are speaking. "That" keeps a listener engaged because it lends anticipation to our speech, whether used in a conversation or a formal speech. It's true for any level of speech and perfectly acceptable. The opposite is true when writing. "That" is by far the word I delete most often. It's totally unnecessary in most writings and should be eliminated 90% of the time. The remaining 10% tells you it shouldn't be completely eliminated from all writings. Using it sparingly is key. Here's a relevant example. In the sentence above, I said, "The remaining 10% tells you it shouldn't be completely eliminated from all writings." The vast majority of people would write, "The remaining 10% tells you that it shouldn't...