Why was mona a in pll?

Mona Vanderwaal was a central character in "Pretty Little Liars" primarily as the original "A," the mysterious antagonist who tormented the main characters. Initially, she appeared to be a friend to the Liars, but her involvement in the "A" game revealed her complex motivations, including feelings of jealousy and a desire for control. Her character added depth to the storyline, showcasing themes of betrayal and the impact of bullying. Ultimately, Mona's actions were driven by her desire for acceptance and recognition in a world where she felt marginalized.