Although it would be a huge disservice to label WandaVision as a great mystery and nothing else (it's also a superb examination of trauma, loss and guilt, after all), it's difficult to ignore just how well the series has kept audiences guessing and in turn how it's cultivated online fan discussion in a way only something from the MCU could.
The series is now approaching its endgame however. Episode seven (or "Breaking the Fourth Wall"), finally unveiled the big mystery surrounding Kathryn Hahn's Agnes, who is really the witch Agatha Harkness, and in doing so recontextualised Wanda's experiences in Westview thus far.
Not fully of course - it's clear Wanda has created the Hex and that she's been powerful enough to bend reality to her will - but for those who had suspicions that someone was benefitting from her trauma and that Wanda was still being manipulated in one way or another by a party or parties unknown (i.e., me), there will have undoubtedly been a small sense of vindication that accompanied the reveal.
It's not as if fans didn't have their doubts as to Agnes' true identity from the off either. Many had Hahn nailed on to be revealed as Agatha at some point, but there are still plenty more who may not be familiar with the character, her importance to Scarlet Witch in the comics, or why her history as a mentor to Wanda may yet lend doubt to the idea that it really was Agatha all along.
If WandaVision should've taught viewers anything, it's that jumping the gun and grasping at conclusions straight away is never a good idea. There are still two episodes left, and there's still plenty of mystery left to be revealed, so let's see what diving into Agatha Harkness' comics history may yet reveal about WandaVision's fast approaching finale...