"Can't decide whether to Shield spell or not.". You urge then to move on, so they say No. It happens again. Enemy melee attacks mage. Pause combat with prompt. You wait. They can't decide whether to Shield spell or not.
Yeah. It could make gameplay very painful.
If your are going to play with someone who's such a pain in the ass, there's very little that will save you from feeling butthurt, reactions or not.
In before "But what if he's going to the bathroom at every round?".
