I cannot get my head around how you are supposed to move around and stay alive when the movement in D3 appears to be so slow.
I feel like my character is swimming in treacle the whole time - even walking between vendors in town is so tedious I feel like quitting instantly because it's so boring moving across just a few meters of open ground to sell an item.
I can't keep up with parties (even vaulting repeatedly), I'm always behind, and monsters teleport on top of me so much faster than I can run away, position myself and/or attack that I just die repeatedly with no chance of a fair fight. I'm playing a level 13 Demon Hunter.
In D2 you could run around, dodge stuff, and generally have a chance of getting into position fast enough to plan a fight (or run away) against a nasty pack. There was a lot of open ground to cover (Act 1 for example) but you could dash across it quite fast and not waste too much time just traveling from A to B.
You can't run anywhere in D3 and crossing a screens-worth of open ground takes ages of boring slow-motion swimming.
Is it me? Is it my Mac? Is it my settings? Is it my connection? Is it my gear? Or is it just how the game is?
Sounds like graphics lag to me. I get it too in some areas with a lot of mobs / fire / pots breaking. It's because my PC is crappy and can't quit ehandle the more resource heavy parts of the game. Sounds like you're having it non stop though so that sucks :/