Even after running for 12 successful seasons, The Big Bang Theory left behind a surprising number of storylines that quietly disappeared along the way. One of the most noticeable examples was Raj’s deep attachment to his Yorkshire terrier Cinnamon, who initially seemed destined to become a recurring part of the group’s dynamic before fading almost entirely from the show.
Similarly, Sara Gilbert’s Leslie Winkle started as a sharp and memorable presence in the early seasons but was gradually written out after Season 3, leaving fans wondering what could have been. Sheldon’s assistant Alex Jensen followed a similar path, appearing briefly in Season 6 before vanishing without explanation.
Meanwhile, Penny’s attempts at self-improvement — including her business ventures and college classes — often showed promise but were rarely allowed to develop long-term. Together, these unfinished arcs remain some of the sitcom’s most curious missed opportunities.