I actually think Protoss need the most micro and Zerg need the least base micro. Zerg rely on position more than any other race though, so you have to micro them in battle flawlessly just to stand a chance. As zerg I really only have problems with Terran and Protoss immortal pushes (latter less annoying). Since I'm in platinum I don't fight clueless Terran (usually Platinum, Diamond, or Master). So I almost always lose to terran because I can never find ways around their damn wall xD. It may seem Trivial, but it is very frustrating when you outnumber your enemy by literally like 100. Yet you can't win because their 30 units can hold off your maxed army. The only way I ever have won vs Terran is when I get Ultralisks to tank, Tank fire. Not just getting Ultralisks though, getting them stupidly fast (12 min ultras, just try replicating my mad skill while holding off all possible cheese xD)