Never assume that you know everything about your customer or vice versa. Assumptions spoil the relationship. Listening is the best tool to combat assumptions. Keep listening to your customers, at all times, at all touch points, because only very few customers actually bother to spend their time to give feedback.
Use all the possible methods to capture feedback, without being too inquisitive. Feedback kiosks are a great option. It is physically available at the touchpoint and customer tends to just click one of the smileys to express his appreciation or dissatisfaction.