Using 'ahead of time' expresses good planning or efficiency. It shows that someone took extra care to be prepared.

Planning Positive

'Ahead of time' often implies eagerness or excitement about the upcoming event or appointment.

Positive Implication

Being 'ahead of time' can imply that you'll have a calm and unhurried experience, without any rush.

Being 'behind time' often gives a poor impression, suggesting poor planning or lack of consideration for others.

Arriving 'behind time' can cause stress for both the person who is late and those waiting for them.

'Behind time' can indicate unexpected delays, not always someone's fault, like bad weather or traffic.