A variable named `t`, `temp`, `data`, `result`, or any other identifier that requires the reader to inspect its assignment to know what it holds.
Variable names match the domain role they play, not their implementation type or scratch nature.
Before the refactoring
const a = height * width;
After the refactoring
const area = height * width;
Every reader pays a re-comprehension cost when they encounter the variable; bugs hide in the gap between what the name suggests and what the code does.
The IDE renames code, not the world around it — cross-repo greps, commit history, comments, and string-literal references silently drift stale.
Reading the variable's name tells the reader everything needed without checking its definition.
Renaming bikeshedding — endless rename churn for marginal clarity gains while the actual code structure stays unimproved.