Now I'm curious: what happened to Tallien to consider him a worse loser than Barras? I only know his involvement in Thermidor and the fact that Theresia left him after all the mess he did to go with a richer banker... Did he embarrass himself in other ways?
How much time do we have? Look, I don't know a lot about Barras, but nothing - nothing - can be as embarrassing as Jean-Lambert Tallien. He is the biggest loser both in terms of "a flop" and "who lost during the revolution" (and he lost more than many people who ended up guillotined, imo).
And I don't even know how/why it happened! He started out okay - he had modest skills but seemed honest about the revolution. Then Bordeaux happened. Thermidor and months after were Jean-Lambert's five minutes of fame, but then it dissolved quickly, both in his professional and in private life.
The Quiberon Invasion mess in 1795 is one of the first examples, when he and Hoche (well, Tallien mostly because it was his orders) executed 750 royalists even after promising they'd be treated like prisoners of war. Yes, those were royalists who made an invasion on France so it's not surprising that they died, but 1) Hoche I think promised they'd be spared but Tallien ordered the execution, 2) Tallien was the one who ran his mouth so much after Thermidor about sparing people and now he executed in one day half of the number of people that were executed in the entire Great Terror, and 3) Seems like Tallien had some pro-royalist dealings/conversations with foreign powers (Spain mostly) and wanted to do a cover-up (? - will need to look into this further).
In his private life, Theresia wanted to leave him as early as 1796 and was reportedly banging Barras, but Tallien begged her to give him another chance. She said yes, and 9 months later she gave birth to a stillborn boy. We are not sure if the baby was Barras' or Tallien's.
Life in the Directoire was not great for Jean-Lambert and he was struggling with money, so he joined Napoleon's expedition to Egypt. It was horrible; he was miserable and suffered health problems. He wrote clingy letters to Theresia ("Care for our daughter and be faithful to me, my love!") (Spoiler: She was already on kid number two by the banker). The letters were intercepted by the enemy and read publicly. On his way from Egypt, Tallien was arrested and spent some time with the enemy but was released. Coming back from France must have been horrible, though, because Theresia asked for a divorce (and by the time it was done, she was already pregnant with banker's baby number 3). Because the kids were technically conceived while she was married to Tallien, they later successfully asked to have Tallien as their last name and were known as "Tallien bastards" in the family.
After, it was just a series of bad circumstances and decisions. Theresia remarried, to a Belgian prince, and we have a letter where Tallien begged her not to do that. FouchƩ tried to help him and found him a job in Alicante. But it was horrible because the whole town was infected by the Yellow Fever. Tallien contracted it and lost one eye. It is also possible that this is where he got leprosy (?)
When he got back to France, he was a ruin. He supported Napoleon in 1815, hoping to get some influence (I assume), but then Waterloo happened so another bad call for Jean-Lambert. He lived in poverty and only escaped banishment during the Bourbon restoration because of his poor health. He died at 53 of leprosy (at least wiki claims so - I could never verify it but we know he suffered poor health for years).
And on top of that - on top of that! - his magnum opus, his legacy, the thing that lives on for 200+ years, is not associated with him. Nobody knows of Jean-Lambert Tallien and his most crowning achievement: the invention of the Terror and evil mastermind Robespierre. Sure, he wasn't the only one involved in that, but he did play a crucial role and, arguably, it is the most historically important thing that he did. And nobody knows it was him! So many people hate Robespierre for 200+ years, but nobody knows who is responsible for forging that smear campaign. (Yes, I am aware that it's the point: if people knew it was constructed, and by specific people, they wouldn't view it in the same way, because the main thing about the Terror how it's seen is that it's an objective thing that happened just as described. But allow me this Tallien rant).
So.. yeah.