I have to take a lot of phone calls and listen toa lot of voicemails for my work... and I think it's really funny that whenpeople leave a voicemail, almost everybody starts off by saying 'Yes' or 'Yeah'... like, every voicemail is always "Yes, hello, my name is John and I'm calling about...", or "Yeah, hi, my name is Jane and I was calling to ask if..."... 
 
I think it's something about leaving a voicemail that just compels people to start off with "yes" or "yeah" subconsciously??? I can't imagine I'd ever write that in a text message, "Yes, hi, what's going on? Wanna meet up for dinner later?"... Or even saying that in-person would feel silly... like being in the line at the grocery store and saying to the cashier "Yes, hi, have a nice day". 
 
Sorry, I don't really have a question. But I just noticed that this was a thing (I think I probably do it too if ever I leave a voicemail), and something about this I find to be very amusing... and I am using this questions page here just to write about my amusement.
the rabbit hole of speaking mannerisms, or for that matter written mannerisms, is perhaps deeper than you ever thought possible