Saying thank you is showing your friend or partner that you notice the ways they are contributing to the relationship.
People contribute to their relationships in many different ways.
Some of these ways may seem small or inconsequential to you, yet to the one contributing in these ways, they are a statement of love and caring. A young couple came to see us in counseling. Both worked full time, juggling their schedules so at least one parent could be home most of the time. They saw each other very little and the time they did have together was poor in quality. Each was seeing the other in terms of not doing, or not contributing.