Andrea represents one of the biggest character deviations in The Walking Dead, but why do fans prefer her comic incarnation so much? Many of The Walking Dead's central figures are faithful adaptations of their comic counterparts, with Rick, Michonne, Carl, Negan and Maggie all portrayed more or less the same between page and screen. However, there are also some huge departures in terms of characterization. One is Carol, who dies weakly in the comics but became one of the TV show's most formidable characters, and the other is Andrea, who did virtually the opposite. In Carol's case, AMC's The Walking Dead took a minor character and turned her into something entirely fresh, but with Andrea, the series already had a strong character, but failed to make the most of what Robert Kirkman had already developed.
Played on TV by Laurie Holden, Andrea immediately gets off on the wrong foot with viewers by chastising Glenn for saving Rick and waving a gun in the protagonist's face. This creates entirely the wrong first impression, painting Andrea as someone who wouldn't go out of their way to save another, someone who would rather point blame than deal with the problem at hand - a hindrance, rather than a hero. Andrea developed somewhat from that early misstep, taking well to marksmanship and adopting a more survivalist attitude, but she also kept rubbing against the audience. Other survivors resented Andrea for not being a team player, she accidentally shot Daryl by being over-zealous, and she made an alliance with The Walking Dead's first major villain, The Governor. Ultimately, it was David Morrissey's character who killed TV Andrea, but she at least departed with a moment of strength by taking matters into her own hands.
In comic book form, Andrea is very different. Rather than an annoyance to her fellow survivors, Andrea is as useful, strong and level-headed as anyone among the main cast. Like her live-action cousin, Andrea is a good shot, but uses these abilities to take out walkers, rather than fan-favorite characters played by Norman Reedus. Even when Andrea decides to strike out alone during the prison arc, she eventually returns to help her friends fight against The Governor, proving her loyalty by risking life and limb. As a reward of sorts, Andrea survives much longer in the comics. She becomes Rick's lover (a position taken by Michonne on TV), acts as the sniper of Alexandria, and only dies at the very end of The Whisperer War in a heroic moment of self-sacrifice.
On The Walking Dead's TV series, Andrea was undoubtedly a good person with her heart usually in the right place, but she was an antagonistic force usually tasked with creating problems for Rick and the others rather than helping solve them. This meant Andrea developed a reputation for being annoying among TV fans - always on the wrong side of events while comic Andrea would be right in the thick of the action helping out. This doesn't necessarily make Andrea a bad character on TV, nor is it any reflection on Holden's performance. Parallels can be drawn with Breaking Bad's Skyler, who attracted the audience's ire not because she was a bad character, but because she wanted to hinder Walt's meth career. And she did things with Ted. Similarly, Andrea pulled Rick back in The Walking Dead, and was usually whining whilst doing so.
A crucial difference, however, is that Skyler fulfilled the role she was meant to play, even if fans didn't empathize with her as much as they should've. On the other hand, The Walking Dead's comic series proves Andrea could've been far better utilized. One could argue that with Carol's elevation and Michonne's introduction, there wasn't room for another badass among Rick's band of survivors, but the change in Andrea's comic character started long before Carol's evolution and even longer before Michonne arrived. And even then, comic Andrea is a different type of badass than both Carol and Michonne - more open, hopeful and likable. Holden herself has expressed dissatisfaction over not getting to play a more authentic Andrea, and it's certainly hard not to imagine what could've been. A comic-faithful Andrea could've added more heart to AMC's The Walking Dead, a series that has often been dominated by more brooding types.
The Walking Dead season 10 is currently on hiatus.