Your Search Terms report shows 2,000 queries. You review them one by one, add negatives, and move on.
The problem: You're looking at trees and missing the forest.
Example:
You have 47 different search queries containing the word "free":
"free project management tool"
"project management free trial"
"free alternative to asana"
... 44 more
Reviewing them individually, some look okay (free trial intent). But in aggregate, the word "free" across all 47 queries costs $3,200/month with 0.3x ROAS.
N-Gram Analysis reveals this pattern in one row: free | 47 queries | $3,200 spend | 2 conversions | 0.3x ROAS
One negative keyword ("free") eliminates $3,200/month in waste across 47 queries.
That's the power of pattern-level analysis vs query-level analysis.