Best before date is about quality and not safety. The food will be safe to eat after this date but may not be at its best. Its flavour and texture might not be as good. The best before dates appear on a wide range of frozen, dried, tinned and other foods.
Mindfulness isn’t about making bad thoughts go away, but about seeing them as mental events. Imagine standing at a bus station and seeing ‘thought buses’ coming and going without having to get on them and be taken away. With gentle persistence this is possible.