"The Big Bang Theory" includes a number of essentially pathetic figures. There's Sheldon, whose arrogance and narcissism tend to alienate everyone he encounters; Leonard, whose incredibly low self-esteem gets in the way of his professional and romantic lives; and Stuart Bloom (Kevin Sussman), whose entire life seems like one giant cosmic joke at his expense.
And yet, arguably the most tragic figure on the show is Raj Koothrappali (Kunal Nayyar). For a long time, Raj suffers from selective mutism that renders him incapable of talking to women. But inwardly, Raj yearns to meet his dream woman, fall in love, and start a family. Eventually, Raj gets over his medical condition and actually starts dating women, where he has a natural edge over his friends due to his intensely romantic nature.
But his dating history is one disaster after another. For a variety of reasons, each promising relationship ends up a dumpster fire, and Raj is reduced to pitiful weeping over the state of his love life on more than one occasion. The worst part is that while all his friends enter into steady relationships, Raj remains an unwilling bachelor until the very end of the show. You have to hope that somewhere down the line after the end of "The Big Bang Theory," Raj finds that one person he can finally settle down with.
