If the other person can't follow your train of thought, it can feel as though the emotional and cognitive connection/trust that was built in the conversation was abandoned along with the previous context. This can happen when there is a non-trivial jump in context between ideas.

Steering the conversation can be done by introducing intermediary steps that are connected to the previous topic in a self-evident way. This maintains that cognitive and emotional connection/trust because you are showing that you value the other person's understanding and participation.

Figuring out what "non-trivial" or "self-evident" means is probably the hard part but you'd probably want to consider each step in, for example:

Grass, meadow, forest, tree, timber, log truck, mill, paper, exports, shipping dock, ocean, ice caps, ice bergs, titantic, James Cameron, Michael bay, transformers.

You could probably go from each one to the next trivially, steering the conversation from grass to meadow and so on through the list. But to go from grass to transformers without intermediate ideas truly makes absolutely no sense.