The concept of microagressions is backwards and pernicious. People are imperfect communicators. Getting offended at cryptic, imagined, or unintended slights is something that children and crazy people do. Adults, especially in the workplace, should be able to understand people have different ways of expressing themselves and that's not bad and you don't need to get HR involved.
One example comes to mind - I had a coworker who frequently wrote "..." After messages on our instant messenger. Once I asked him a question and he just replied "..." And then 20 minutes later told me the answer. I read this as kind of a sarcastic thing, like an exasperated sigh that he'd have to explain something so obvious. I thought this guy was a real jerk.
One day after he sent me a "..." I asked him what it meant. I said "What does '...' signify?" And the guy answered that it meant "More to follow" and I realized that he wasn't being a jerk, he was just trying to signal to me that he couldn't complete the answer at the moment, but would send more to follow.
The point of my little story is that it just doesn't make sense to assume hostile motives. Lots of times people just communicate differently. Trying to document all the times you can interpret someone as being negative is just a bad idea in addition to being unfair and unproductive. It's also way more likely to make people genuinely aggressive and hostile towards you.
