USE THE APPROPRIATE LEVEL OF FORMALITY

People are sometimes tempted to use informal writing in informal digital applications such as email and microblogs. Don’t. Everything you write on the job is legally the property of the organization for which you work, and messages are almost always archived digitally, even after recipients have deleted them. Your documents might be read by the company president, or they might appear in a newspaper or in a court of law. Therefore, use a moderately formal tone to avoid potential embarrassment.

TOO INFORMAL Our meeting with United went south right away when they threw a hissy fit, saying that we blew off the deadline for the progress report.
MODERATELY FORMAL In our meeting, the United representative expressed concern that we had missed the deadline for the progress report.

However, you don’t want to sound like a dictionary.

TOO FORMAL It was indubitably the case that our team was successful in presenting a proposal that was characterized by quality of the highest order. My appreciation for your industriousness is herewith extended.
MODERATELY FORMAL I think we put together an excellent proposal. Thank you very much for your hard work.