Warning: SPOILERS for WandaVision Episode 1
Avengers: Endgame, Wanda finds herself in a surprising, newly-married suburban life with Vision (Paul Bettany) that emulates 1950s sitcoms. As WandaVision makes clear by the end of its first episode, the TV approach is no accident, and it also includes a fake commercial for a new Stark invention.
Through this commercial, WandaVision begins to remind viewers, and potentially Wanda herself, about a forgotten part of her origin story. The fake ment is for a brand new Stark-brand toaster. While that might not seem like much of a connection to the role Stark unknowingly played in Wanda's past at first, the toaster design indicates otherwise. The toaster has a small red light that blinks and beeps, with the blinks/beeps getting faster to show the toaster is almost done and ready to pop. This design makes the toaster's countdown sound exactly like a bomb ticking down before it explodes. With the man and woman featured in the commercial standing right next to the toaster when it "pops," this is a clear reminder of Stark's role in Wanda's origin.
Wanda's story in the MCU began in Hydra's experiments to get powers and originally team up with Ultron.
While Wanda has seemingly moved past the fact Stark is partially responsible for her parents dying, the reference in this commercial could be a sign that this isn't totally true. Wanda might not have a desire to get back at Stark after Avengers: Age of Ultron, but WandaVision could suggest that she never really forgave him. Instead, this commercial could be a manifestation of a repressed memory that Wanda has. She likely has tried not to think about this moment much over the years. WandaVision could be planting the seeds for Scarlet Witch's deteriorated mental state with a quick reminder of the pain that is in her past.
So far, WandaVision has only offered up small teases of what is really going on with Wanda and Vision. But, it does appear that Wanda has some semblance of control over the altered reality they're now living in. Past trauma like the loss of her parents, the death of her brother Pietro, and Vision's death in Avengers: Infinity War could all be memories that Wanda is trying to forget about with this new life. In fact, WandaVision presents her and Vision as having little to no clue about their pasts. While they should unravel the mystery as the show continues, Marvel appears to be using commercials like this one for a Stark toaster to remind viewers of Scarlet Witch's MCU story.