You message should convey the same courtesy to your callers as a person would who is speaking to someone in your office. Saying things like "thank you for calling" and "have a nice day", in addition to watching your tone of voice, will help you to represent your office in a compassionate and professional manner.
The simple truth is that you need to be more aware of what you’re leaving for other people to hear. Sure, this doesn’t always register as a priority for users, but it’s never too late to reassess your greeting. a. Reading/Speaking in the Imperfect Tone: Tone is absolutely everything. Users don’t want to come off as being too nice, as it sounds insincere, or being too terse, as it can be interpreted as being rude. That being said, striking the right balance is absolutely essential. Your greeting exists as its own entity, and therefore, it should NOT rely on callers’ familiarity with you. Instead, it needs to appeal to the masses. As such, your inflection, i.e. the way you state your name and directions, needs to be both welcoming and firm. b. Injecting Humor & Insincerity: While humor/light heartedness can be welcoming, it can also convey a sense of informality, insincerity, and ultimately unprofessionalism. Why, because you’re not there to lend your humor or to contextualize. Instead, you’re assuming the caller has a working knowledge of your personality to ground the message. Though this might not sound like it’s all that terrible—it can be detrimental. As stated above, one should NEVER rely on a caller’s familiarity with you. Instead, aim to appeal to the masses. Humor is ultimately subjective, meaning not everyone has the same tastes; therefore, someone is bound to be turned off by a quirky or off-color remark. While implementing a light-hearted or even tongue and cheek tone can work, it’s just a really bad idea.

Have a positive attitude while recording your voicemail greeting — it will carry through in your voice. If you find it difficult to convey positivity over a phone system, try smiling while you’re recording. (We promise, you will hear a difference.)
12. “Hello, you’ve reached the Customer Support department at [company name]. We are unable to take your call at the moment. We know your time is valuable so instead of placing you on hold, let us call you back! Please leave your name, phone number, the reason for your call, and two different times that are convenient for you to receive a call back from us. Thank you!” Get a better idea of your caller’s schedule by asking them for a few different times you can call back. Their time is important, too!