“It's becoming a habit, though.”
Become a habit means to develop into a repeated pattern. The progressive It's becoming emphasizes gradual change. About another person's behavior, it can express frustration that it keeps happening.
B1-60 / CEFR B1 / EPISODE 60
Expressing disappointment before it builds up
SceneTina canceled their Saturday plans at the last minute. Frank hasn't told her how he feels for two days. Now they're at his table. Tina picks up the cup beside Frank.

WORDS & CONTEXT
Become a habit means to develop into a repeated pattern. The progressive It's becoming emphasizes gradual change. About another person's behavior, it can express frustration that it keeps happening.
Bother can mean to annoy or trouble someone. That's what bothers me. calmly identifies the source of concern rather than attacking the listener in anger.
Turn down means to refuse an invitation or offer. It is more conversational than refuse or decline. Frank declined another invitation so he could meet Tina.
Demanding means expecting or requiring a lot. Frank stayed silent for two days because he worried that asking Tina to keep her promise would sound demanding. Sound … describes how words come across to the listener.