Warning: the following contains spoilers for My Senpai is Annoying Episode 6, "Grandpa Hearts Futaba," now streaming on Funimation.
In My Senpai is Annoying, Futaba Igarashi is determined to prove her worth at the office, and she doesn't take kindly to anyone who patronizes or mocks her in the process. Futaba puts herself under a lot of pressure to succeed on her own merits, and a brief flashback in Episode 6 makes it clear that she has always been this way.
In Episode 6, Futaba's grandfather, Mr. Igarashi, visits on her birthday and immediately becomes overprotective of his granddaughter. Futaba finds this obnoxious, and Mr. Igarashi later explains to Harumi Takeda that Futaba has always wanted to be self-sufficient and owe no one any favors -- a trend that continues today.
Mr. Igarashi means well, and he has his granddaughter's best interests at heart. Even though Futaba finds him overbearing, Mr. Igarashi still rushes to her defense at the slightest provocation, making him something of a counterpart to Harumi Takeda. Their similarities draw Mr. Igarashi into a feud with Takeda to see who is more worthy to be Futaba's defender, much to her chagrin. In most aspects of her life, she only needs herself, but Mr. Igarashi knows this deep down.
Once Mr. Igarashi and Takeda call a truce, Mr. Igarashi explains that Futaba has always been a hard worker who took great pride in her accomplishments, and right before starting high school, she resolved to move to Tokyo by herself and succeed on her own merits. She didn't want to owe her grandfather anything and took the challenge head-on. Back then, Mr. Igarashi gave his granddaughter his blessing, and as hoped, Futaba thrived in Tokyo, from high school to college to the workplace. Her independent streak continued to the present, to the point where she can't stand the idea of someone else fighting her battles for her or owing anyone any favors, even if she has a genuine need for them.
Eventually, Futaba, her grandfather and Takeda all get on the same page, with Mr. Igarashi and Takeda resolving to look out for Futaba only when she seriously needs it, a decision Futaba is decidedly grateful for. Futaba (occasionally) truly does appreciate Takeda's help, especially in light of her blossoming feelings for him, but she clearly doesn't want him or her grandfather hovering over her every hour of the day -- and it's not even necessary. Futaba knows how to rely on her friends and family while also building up a successful life on her own, and she gets a great deal of validation from it. As a student and a working professional, she has a clear need to accomplish these on her own, to the point where she might feel insulted or guilty if she has to rely too much on others.
These insights into Futaba's character are consistent with her earlier antics in the series so far, like when she quickly repaid Takeda for looking after her while she was ill, and how she worked hard to make chocolates for him on Valentine's Day. Futaba also reacted quickly when she botched a report to a client and worked overtime to fix it and smooth things over. Futaba is a person who wants to earn everything she gets, and she only relies on friends and family when the need truly arises. Futaba is independent-minded and hardworking, but not ungrateful. She's more gracious than that, even if she has a serious tsundere streak and has a hard time saying "thank you" afterward.
