So far, scientists Leo Fitz and Jemma Simmons have been the weakest characters on Agents of S.H.I.E.L.D., aside from Grant (who suffers from Riley Syndrome, in the sense that just like Riley from Season 4 of Buffy, I emit a loud "ugh" every time he appears on screen). The two scientists are so obnoxiously redundant that they're rarely even called by their individual names, instead being referred to jointly by the team as "FitzSimmons." The show seems to know this on some level, so the latest episode, "F.Z.Z.T," makes an argument for their relevance.
The concept is simple: There's a deadly alien virus in a helmet left behind from the New York invasion. (Okay, maybe it's only simple in the world of S.H.I.E.L.D.) Through the team's investigation of the virus, Simmons catches it. Suddenly, she's quarantined and racing to find a cure for herself while Fitz looks on helplessly. It's here that we get some insight into Fitz and Simmons' relationship, most of that insight being that they are always together. But it's a sweet sentiment, and it helps define their roles in their relationship apart from being one chittering, precocious mass.
Of course, Fitz risks contracting the virus being quarantined with Simmons, in his efforts to help her find the cure. The rest is more or less predictable: They don't figure out the cure until all hope is lost, Simmons sacrifices herself so she won't put the team in danger, and she's rescued just in the nick of time. Simmons thanks Fitz for helping her, and then, after all the romantic buildup in the episode and high emotional stakes, she merely kisses him on the cheek.
Which begs the question: Why should we care about "FitzSimmons"? The show seems to suggest a budding romance between them. It's a possibility that could be exciting, but ends up being a disappointment, mostly for one reason: The satisfaction of seeing any two characters pair up on a show comes from seeing those characters as fully-formed individuals whose relationship changes in nature. Fitz and Simmons are currently barely indistinguishable from one another and already bicker like a married couple. There's no risk in their relationship right now, and no reward for the audience if they get together.
Their relationship was the both the central part of the episode and the least exciting part, and this is an episode in which Simmons jumps out of a plane. But honestly, what can the show even do with them at this point? "FitzSimmons" is essentially one character in two bodies, and watching a person have a relationship with themselves does not make for interesting television. Nor does watching two versions of the same character follow each other around.
Fortunately, the show has a lot of spark with Agent Coulson and Melinda May. Coulson has now realized that he was dead for quite a while and something in him changed when he came back to life. But May eases his fears for now by telling him to take his shirt off. (It's not what you think, pervs.) Yet another storyline tease about Coulson being "revived" in Tahiti, but at least it's more exciting than watching "FitzSimmons." It also brings the hint of a promise of yet another relationship on the S.H.I.E.L.D. plane. So even if the whole "FitzSimmons" relationship is doomed to be a dud, we can at least take bets: Who's going to make out on the S.H.I.E.L.D. plane first?