Getting the Last Word In
While sometimes trying to "get the last word in" could be considered a negative, let's twist it a bit and make it a reminder to follow-up and close out conversations. It can be especially easy in the current climate of online conversations and messages that go back and forth frequently to forget that business communications should come with business structure.
Remember that if you are communicating for business purposes, then emails should still be structured as a letter, with a greeting, a sign-off, and a signature. Without those things, it can feel too informal or incomplete. You also really need to remember that "thank you." If you are asking someone for something, be it a service or information or even their time and consideration, a thank you should be something that is automatic to you. If you are a business person and you are responding to someone, make sure to thank them for their questions, concerns, etc. It is a small gesture that holds a lot of meaning, and it is the bare minimum in customer service.
Follow-ups are necessary outside of simple inquiry emails as well. Make sure you connect with the people you met at networking events with a note of some sort - it formalizes those connections and is the reason you swapped cards. Take the time to thank interviewers for their time when you are interviewing for a job, and that you thank applicants who applied for your open positions. Close out those conversations and connect with people. It is too easy to not follow up, and people notice. Not completing those communications makes a negative lasting impression. Take the time to get that last word in.