When the payment was cancelled through the customer somewhere.
When the payment has been created but is not confirmed yet. Eg. When waiting for a SEPA transfer to happen.
When the payment could not be processed due to an error. The error data with more information is saved on the payment.
When the payment has ben successfully paid.
When the payment has been refunded to the customer.
When the payment has been reserved/frozen but not yet collected.
The different status a payment can have.