I just faced a terran who did a 2 base mass marine, hellbat, mine all-in with two tanks and a random thor(?). I did a stargate opening and just scouted it as being normal mech opening (they kinda hid the barracks). Having seen it, it'd be easy to hold off with storm/immortal/archon. I just got blind-sided by it.
I don't put a lot of thought into these losses usually because it's ladder, there's no way to know it's coming, and I'm never gonna see this again, but it can be frustrating.