There's something wonderful about fierce old women. Ancient broads who have put up with all the bullshit in their lives and now, in their wrinkled dotage, aren't interesting in putting up with any more. They've raised children and endured husbands and navigated a world that demanded they be sexy when young and pure when married and nurturing when motherly and conveniently forgotten when all three are finished. They've been overlooked or objectified or oppressed or overworked or all of the above and they have a unique perspective on the world's ills. I've had the pleasure to labor alongside - and sometimes the bad luck to fall afoul of - these kinds of dowager dynamos in local political life, and I can testify that there is nothing as dangerous as a grand dame fighting for the world she wants her grandchildren to inherit. They have nothing left to lose, because it's all been taken away at some point during their lives, everything except their depthless wisdom and a hard-earned, if sometimes threadbare, dignity.
The Queen of Thorns from Martin's Game of Thrones is just such a weathered warrior-woman, bringing a acidic tongue and cruelly biting wit to bear alongside her drill-bit intellect and complete lack of scruple to do whatever it takes in pursuit of her house's protection and advancement. There are no soft edges to Lady Olenna, no knitting or baking or empty praises, just unvarnished truth and an unmatched strategic mind. She'll play the broken-down old biddy when it suits her, but she's more than capable of trading barbs with royalty and plotting murder and coming out smelling like a rose. She's caustic and wonderful in the books, but there's something perfect about Diana Rigg's portrayal in the HBO series. Rigg, once a Bond girl, was also Emma Peel in the popular 1960s show The Avengers. When she found out she was being paid less than a cameraman on that show, she held out for more money and then she quit. Now that's something Olenna Tyrell would have done.