no enemy on other side but when i can choose new cart i must choose enemy to hit. But there is no1 to hit... no cancel option nothing or im blind. i can attack my unit to make move. Maybe decription is not good enough [PL]

IF you use an ability at the start of a turn, it forces you to use a card from your hand before you can pass.

IF you select certain cards or charges, it LOCKS you into using the card i.e. a card's charge that pulls a random from your graveyard- you are stuck having to play it.

SOME cards have very specific criteria. If it says you must damage something and no enemy is on the field, it means you have to select an ally (for good or bad).

IF using a controller and doing a puzzle for example, you have to cancel the puzzle info panel on the left.

Hopefully something above covers what you are asking?