The first episode of 'THE TaeTiSeo' aired on On Style on August 26, and featured special guests like Heechul and YoonA.  On this day, there was a lot of discussion about the members' character, particularly Taeyeon.

Tiffany said, "Taeyeon is a really interesting person.  It's hard to get a grasp [of who she is]."  Seohyun added, "Taeyeon is the type to take care of you without you knowing. She doesn't say, 'I will do this for you,' to your face, but she takes care of you behind your back."

Heechul said, "Taeyeon's emotional ups and downs are really severe.  Seeing as how both of our emotions fluctuate severely, we are called the Kim Bipolar siblings. Her personality really matches XX.  I can't say this any other classy way.  The reason I like Taeyeon is because she's not fake.  She treats people with honesty.  She knows how to take care of her friends."

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Key said, "Taeyeon is number one when it comes to an ahjumma personality. When she laughs, she laughs like, 'Ahaha,'" and copied her laugh.

In addition, Taeyeon praised Tiffany, saying, "Tiffany is very passionate.  She's a character that relays happiness.  Seeing as how she has so much energy, there are times it's hard to follow her."

Meanwhile, YoonA promised to appear as a guest on 'THE TaeTiSeo' at a later time, saying, "It's TaeTiSeo's reality program, so I feel like it might be good to have only TaeTiSeo come out in the beginning.  After about the middle of the program, after TaeTiSeo establish their positions, I will appear as a guest."

Hearing this, Seohyun lit up with a bright smile and hugged YoonA.