Each color represents a relationship between the two adjacent words. (You can figure out which color means which relationship by guessing for a few pairs, keeping a consistent interpretation of one color, and seeing whether that consistent interpretation breaks anywhere.)
The relationships are:
Red: words in a three-word phrase ("rhyme or reason", "case in point"...)
Orange: Two-word phrases or compound words
Cyan: Added or dropped letter
Purple: Items in the same category
And the final grid looks like this:
This works the same way as the previous grid, but the colors are different.
Light red: Action and object of that action ("wags tail", "smothers fire"...)
Light orange: Noun and adjective describing that noun ("summer --> hot", "confusing --> maze"...)
Light yellow: One-letter change
Light green: Opposites
Light blue: Rhymes
Light purple: letters added or removed to front and back ("white/hit", "amazed/maze"...)
Answering the questions
Each grid is a binary tree, with leaves at the given words: that is, if you only figure out words with two other words as clues, you can fill in the whole grid. The node that is forced to be last in this fill is the one with only two connections, the "root node".
Word 1 | What are you if you don't have directions?
The answer is the root node of grid 1: LOST.
Word 2 | Where might you go if you don't have directions?
The answer is the root node of grid 2: FORWARDS.
Bonus | How might you feel if you don't have directions?
You might be LOST FOR WORDS (which sounds like the two answers, "lost" and "forwards").
Final Answer | Why don't you have directions?
Well, you misplaced the preface: you LOST FOREWORDS.
(Thanks to ManyPinkHats and Level 51 for pointing out the obvious parts I was missing in chat.)