Honestly, 'The Mating Season' always makes me think of Gussie Fink-Nottle first, because the whole mess kicks off when Bertie tries to help him with his wedding plans and, typical Wooster fashion, gets mistaken for Gussie. That lands Bertie at Deverill Hall posing as Gussie, which is the engine for all the confusion. Jeeves, of course, is the steady hand trying to steer the ship away from the rocks, usually while Bertie is busy getting engaged to someone he definitely shouldn't be. Madeline Bassett floats in and out, being her usual soppy self, and you can't forget Sir Watkyn Bassett and the formidable Roderick Spode looming around. The cast is classic Wodehouse chaos.
What I love is how each character is a specific type of comedic gear that only meshes with the others in this one, perfect, disastrous way. Spode’s bluster against Jeeves's quiet competence, Gussie's earnest fish-obsession against Bertie's frantic improvisation—it's a clockwork of misunderstandings. The 'key' isn't just who they are, but the roles they're forced to play. Bertie as Gussie is the central farce, and everyone else either believes the act or is trying to unmask it for their own reasons.