Be careful when you tell people you "might" do something. Are you sure about that? No one is asking you to solve world peace. When you say you "might" finish a report, it implies you lack some ability, don't manage your time well, or have too many priorities.
Here's an obvious word to avoid in your emails. Anyone who says he or she "won't" do something or "won't" attend a meeting is generating a negative vibe. Be more decisive: Either accept an invitation or reject it; using the word won't suggests hesitancy.
This is a trigger word in email that makes it obvious to everyone that you don't have all the facts. If you say the accounting department "usually" doesn't approve your expense report or the boss is "usually" late to work, it means you're stretching the truth.
Unless you are talking about a suspect in a trial, avoid saying you "suspect" anything. You're not Sherlock Holmes. Just use direct terms: You know an investor is pulling out of the project, and here's why; or you have facts to support your conclusion on a new marketing plan.
I'll bet Mark Zuckerberg has never used the word impossible in an email. The recipient will lose confidence in you quickly. State why something might be hard or difficult or just don't agree to a course of action. Don't bother telling people it's impossible.
We all worry about the stresses of life. Telling people you are worried by email makes it seem as if you lack confidence in your abilities. If you are worried, don't bother saying that to anyone--just express what you are concerned about and offer solutions.
Expressing your confusion will create even more confusion. It's better to just say what you are confused about and ask questions. Saying you are "confused" gives people the impression that either you don't understand something or that the topic is confusing to you.
We all have needs in life. When you express those needs by email over and over again, it makes you look needy. I "need" you to come to work early, I "need" you to get that report done. Avoid saying "need" and express requirements more directly.
Have you sent a message and said you were in a "quandary"? You should know that the word means you are in a total state of perplexity. I mean, you are really perplexed. That's not often the case when it comes to a new business proposal or fundraising round.
Few of us are in the business of predicting the future. If you say something is "likely" in an email, you are expressing to the recipient that you are not really sure about the topic, and you don't have all the facts yet. It's likely that you just lack confidence.