In my early days of playing with phalanx I had some devastating experiences.

It was a castle siege, and there was a group of hoplite militia walking towards my hoplites with their spears down. On my end I had my mercenary hoptile welcoming them, also with my spears down. I took the guard mode off and left the phalanx on, no problem.

While they came close I thought "OK, showdown time!" So I order them to "attack". Suddenly all of my green hoplites raised their spears to be poked badly. Needless to say I lost the duel.

So I learned the lesson that "always issued an attack command well before the engagement" for phalanx.