Especially in the UK, we are so used to apologising for almost everything we do, in order to come across as considerate, humble, and not at all shameless. However, sometimes apologising does more damage than good. It makes us and others feel like we've done something wrong while that may or may not be the case. Often a simple 'thank you' will make others feel seen and appreciated for their actions, while we ourselves can feel gratitude and more self-worth.
There is plenty of research on gratitude, its effects on happiness and it's usefulness for countering depression. A simple google search will give you numerous articles about showing appreciation and returning kindness.