What causes his baggins side to reamerge?

Bilbo Baggins' "Baggins side" re-emerges primarily in response to the comforts and stability of his home life in the Shire, contrasting with the adventurous influences of his Took side. The arrival of Gandalf and the unexpected adventure with the dwarves awaken his latent desire for exploration and excitement. Additionally, the influence of the One Ring, which he acquires during his journey, serves to amplify his Baggins traits, leading him to seek the safety and familiarity of home even after his transformative experiences.