Here's a few traps that I fall into myself, and observe time after time when watching other players, the key reasons why Terrans lose:
- Too much fancy micro. Too much time spent microing during a battle or being distracted by something. That awe-inspiring stutter step or marine split looked awesome during the fight, but during this time, production facilities sat entirely idle, or as many as 20 seconds go by before the units are queued up. Which leads us directly into:
- Queue Curse. Your units are all queued up 2 units deep or even to the max in your existing barracks or factories. This is the reason why Protoss always seems to outnumber or outsupply you. Protoss players have it ingrained within them, to constantly warp in more gateways(because warpgates don't have a queue). Thus Protoss players are not nearly as subject to the Queue Curse, which is common with Terrans. Once hailed as a quality of life feature - ability to queue in fact hurts you, more than it helps, and is costing you untold number of games.
- Ineffective multitasking. Your hellion run by did not do as much damage as you think it did. During all that fancy drive-by and dodging, what wasn't happening? SCV's were not being produced on time. More production facilities weren't produced. All those minerals you floated should have been another base + more facilities, but by the time you realized it, you're in truth no further ahead. All that attention spent keeping that Banshee alive cost you *more* than it cost your opponent.