Dumbledore wasn't surprised to see Harry in front of the mirror. It was mesmerizing, seeing one's deepest desires.

Harry saw his parents.

Dumbledore came there every night, desperate. He didn't want to forget how he looked, smiling back at the old man.

"What do you see, Professor?"

Dumbledore turned his gaze to the Mirror of Erised.

He saw a younger him. Why it wasn't his current version surprised him. He was happy with his age.

He saw his old best friend beside him. Grindelwald's arm was hooked around his shoulders, a stupid grin on his beautiful face.

He saw how the one he loved leaned in and kissed his slightly stubbly cheek, still grinning.

His lips curled into a soft smile.

"Well Harry, I see myself holding a new pair of socks."

No, the young boy didn't need to know such a horrible truth.