The above section details types of phrasing to avoid; however, it doesn’t detail what users should NOT say on their greeting. Though this is a bit loaded, as there are hundreds of combinations of things one shouldn’t say, there are some key components users should ALWAYS avoid. a. Forget About Slang: You should strive to be as professional and welcoming as possible in your greeting. While this may steer you towards using slang, in an attempt to make callers comfortable, it’ll most likely work against you. As a professional, your demeanor, tone, and speech should be clear cut and well articulated. Using slang undercuts this and works against you. b. Don’t Even Think About Profanity: This is a no-brainer. Never, under any circumstances, curse in your greeting EVER! c. Keep Your Sentences Clean, Don’t Ramble: Introduce yourself and give your caller specific direction. Avoid long diatribes detailing tangent thoughts. Keep it simple and quick. d. Always Return Your Calls: It’s important for callers to feel they are valued. Nothing dissolves this quicker than a greeting that doesn’t stress this. For example, “I’ll call you when I can,” “If I don’t return your call, please call back”—these phrases are terrible and completely destroy any good will you may have with a caller.
Translation: If you sound unsure, then your current clients, prospects, and partners won’t be so sure about you either.

For example, a message like, “Hi, this is Jim. You know what to do.” Well, not everyone is going to know what to do—i.e. they won’t leave you inclusive information. Additionally, they may not leave you a message at all. Aside from this, humor can again be detrimental to your message, this time lending itself to ambiguity and costing you clarity. For example, if a message read, “Hi this is Jim, sorry I can’t answer your call right now. Please leave your name and number and I’ll call you as soon as I can, but you already knew that right? Do I need to tell you what to do?” This is worse than the previous example as this is confusing and can also come across as rude and unprofessional. Complicating a greeting with phrasing like this is sure to cause some harm. e. Ignoring Personality & Identity: Don’t use computer generated greetings. Some users leave default messages (‘you’ve reached the voicemail box of 777-777-777, please leave a message). Believe it or not, even this can cause problems. Callers may be unsure if the voicemail box belongs to you; therefore, they don’t leave a message. Also, some may even be uncomfortable leaving information through a message in a nameless voice message box. As such, impersonalization can cause ambiguity, which again can hurt the effectiveness of your voice message system. This doesn’t mean you have to make an elaborate greeting if you don’t want to, just insert your voice and name so at least callers know they’re calling the right person.
Website: https://answers.microsoft.com/en-us/skype/forum/all/how-do-i-change-my-skype-voicemail-greeting-the/082783f4-c05d-425b-862e-4589b59cb117