We migrated a team from Unity to Godot - not as beginners, but as experts whose Unity instincts actively worked against us. The habits that made us fast in Unity quietly produced brittle, un-idiomatic Godot code, and the bill came due within weeks.

This is the honest post-mortem of our first month: the mental models that collided, the muscle memory that backfired, and the day source control broke. For each, we'll show what we assumed, what actually happened, and the convention that fixed it - so your first month is shorter and less painful than ours.