Some time ago, one video of Taeyeon with a male fan at a fan signing event went viral online.
It was because the fan was spotted being nervous in such a hilarious way upon seeing his favorite star.

At that time, he tried to pass a flower to her and also reached his hands out to hold her hands.
While he was doing so, Taeyeon noticed his hands were shaking unnecessarily hard and burst out laughing.

It seemed the fan had made a strong impression on Taeyeon, because she remembered him even though she had only seen him briefly a long time ago.
Instead of telling him this in words, she showed it to him; she shook the gift from him side to side after receiving it from him.
After shaking the gift about, Taeyeon laughed out loud and the venue soon filled with her, the fan and all the other fans' laughter.

(SBS Star)