I agree it is extremely irritating, but it is also very useful for quick identification of some individuals who likely also have a host of associated attributes.
However, I noticed that I sometimes do begin certain sentences with "So" depending on the content of what precedes that sentence and the content that follows. I am aware that I do it, but I do try very hard to avoid doing so; I am not always successful. I don't believe my usages are comparable to those referenced in the OP though.
Recent examples of my doing this:
https://poal.co/s/Astronomy/558641/58ac90de-1891-4d68-b26a-986f201641c2 "Of course he said doing that went against every principle of his, but he really needed to make some money on that video due to the time and effort to make it. So his community begged him to add a donation link, even his core viewers who said they'd walk if he put up a donation link were fine with it because 'he was forced to do it by evil jewtube screwing up his video release'."
https://poal.co/s/History/557973/89856794-e4f1-4097-8620-b0bca9dbcecf "Without everyone who has continually posted information on poal for years, I would definitely not be anywhere near as informed on the state of the world as I am now. So I am very thankful for everyone posting things and to AOU and others that there is still a place where things can be posted."
https://poal.co/s/History/557973/456d0c76-9960-40d9-bcd4-2e1646242f6a "I don't believe everything I read, but most things tend to help fit a few more pieces of the big puzzle together. So I accumulate and attempt to read a lot of books other than those I've posted to /s/Books, like:
https://poal.co/s/History/557973/6ea5c1a8-9e65-48ea-abf8-3e1c3b090d29 "In this comment, there is 1 book in two versions. So 1 link if you only want one of the versions, or 2 if you want a copy of both versions." ... So files for 41 different books are linked in it, but one of those books is six stoic books in one."
I do not feel my form of usage warrants my removal from the living. I might be wrong though.
Much worse are those who begin sentences with "I mean" which begins a reiteration of a prior statement for clarity, but no prior statement has been made as "I mean" is beginning the initial statement.
Your usage of the word so is perfectly normal. It serves as a link from a previous statement and elaborates upon it. I don't hate the word, I hate how it's use at the beginning of a sentence by the leftwing press as though it pains them to have to explain themselves. I hate when one of these talking heads like that lesbian press secretary or one of those harpies on a morning talk show start off with it as though everyone is an idiot and that they need to clarify their version of reality as if their opinion is the only one that should exist.
And no, I don't watch any of that shit. The short clip links are about all I can stomach.
(post is archived)