Use 'take aback' to describe an immediate emotional response, especially surprise or shock.

Emotional Reaction

'Take aback' is fitting when something happens that is not anticipated and causes a strong reaction.

Unexpected Events

The phrase doesn't always imply a negative surprise; it can be neutral or positive.

When something is puzzling or hard to understand, 'take aback' reflects a person's state of confusion.

Being taken aback can happen with positive confusion, like being surprised by a compliment.

It's important to make the context clear, as 'take aback' doesn't explain why confusion occurred.