Starcraft – Lagging with theself

This is intended and is referred to as "Smart Casting", and it makes it easier to micro manage your units. In Starcraft 1, you would often over cast your spells. For example, if you had a selected group of High Templar and you casted psionic storm, every single one of your templar would cast psionic storm in the same spot, which is a waste of energy.

It's much more efficient to just press the hot-key of the unit's spell.

As a note, be careful about holding shift before casting any spell. If the unit is doing anything before you queue the spell, the unit will not cast the spell until the previous action is done.

For example, your BCs are sitting there, and then a swarm of mutas attack you. You press and hold shift to queue up yamato cannons, but wait! your BCs started auto-attacking before you could give the yamato cannon command. Now they completly ignore the yamato cannon order until all mutas are dead. This same problem exists for all other spell casting units.

It sounds like you're building a large army and using it to gain map control, but then are falling prey to things like drops and backdooring.

If you have map control your first thought should never be: Crush my opponent, as you're essentially sacrificing an advantage (map control) for an unsure victory (because he doesn't control the map doesn't mean he can't take you). Instead your thought should be: take the map. I think you'll find this change in philosophy will lead to situations where you have a much more powerful economy than him and you're able to kill him with attrition.

Now if you're falling prey to things like BD here is a quick check list for you:

• Are you scouting? an Observer should be the first thing you build out of Robo. If you don't go Robo, a Hallucination works just as well. Sometimes scouting means sacrificing some Zealots in a pointless charge to just get inside his base.
• If you're scouting, are you seeing it coming? Overlords on the edge of your base, Starport with Reactor + 3 Rax, all of these are indicative of certain strategies you should watch out for.
• If you see it coming, how are you responding? If you have map control that means you should be able to respond quickly. Shutting down these back door attempts is often a bigger victory than a straight up conflict
• Finally, Do you have map control? If you don't have map control that means he does, and if he's beating you with map control then your problem is not "how do I deal with a base trade?" but rather, how do I regain the advantage.