The incorrect use of the word "since" is a pet peeve of mine. This means it really only annoys me and no one wants to hear me complain about it. From the amount of faulty usage I see with this word, it does seem only I care about this. I see its misuse with published authors, bloggers, journalists and of course just about every email I receive. So here is your quick lesson.
It doesn’t matter if you use it as a conjunction, preposition or adverb, the word "since" is a reference to time.
Since I was the tallest, I took the books off the top shelf.
There is no reference to time here. It should read: Because I was the tallest…
Since I was in the bar, I had a drink.
It should read: Because I was in the bar…
Since I got my driver’s license, I have only driven red cars.
We have been breathing air since the beginning of time.
Since the divorce, they have not spoken to each other.