Make somebody’s day
Definition 1 of 1
Pro Tip 1/3Emotional Impact
The phrase emphasizes a significant positive emotional effect on someone, usually from a small but thoughtful act. 
Your praise in front of everyone really made my day.
Pro Tip 2/3Sincere Gratitude
Using 'make somebody’s day' suggests genuine gratitude and is often said with heartfelt appreciation. 
Seeing the kids’ smiles made her day.
Pro Tip 3/3Unexpected Joy
The phrase usually refers to a happy surprise or something unplanned that greatly pleases the person. 
Finding that old photo made his day.