Improve README.

README.md

@@ -1,37 +1,59 @@
 [![Build status](https://github.com/schmonz/junit-greencently/actions/workflows/main-build.yml/badge.svg)](https://github.com/schmonz/junit-greencently/actions/workflows/main-build.yml)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.schmonz/junit-greencently/badge.svg?gav=true)](https://central.sonatype.com/artifact/com.schmonz/junit-greencently)
 
-# [Greencently](https://schmonz.com/software/greencently)
+# Greencently
 
-## Setup
+Do you usually run your tests before you commit, to check your work?
 
-For JUnit 5:
+Do your tests also get run by a
+[pre-commit hook](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks)?
+
+This is helpful in the worst case --
+the pre-commit hook has your back when you forget --
+but in the typical case it's harmful:
+
+- Disrupts flow
+- Doubles cost
+- Adds no marginal benefit
+- Discourages frequent small well-tested commits
+- Engenders learned helplessness
+
+We can fix this.
+
+## Setup for JUnit 5
 
 1. Update `build.gradle.kts`:
-```gradle
+```gradle.kts
 dependencies {
-    testRuntimeOnly("com.schmonz:junit-greencently:VERSION_NUMBER_HERE")
+    testRuntimeOnly("com.schmonz:junit-greencently:CHECK_ABOVE_FOR_VERSION")
 }
 tasks.withType<Test> {
     jvmArgs("-Djunit.jupiter.extensions.autodetection.enabled=true")
-    maxParallelForks = 1  // see #4
+    maxParallelForks = 1  // see issue #4
 }
 ```
-2. Run all tests for project
-3. If green, observe top-level `.when-all-tests-were-green-junit5`
+2. Run all tests in project
+3. If green, observe top-level timestamp file `.when-all-tests-were-green-junit5`
 4. Append to top-level `.gitignore`: `*when-all-tests-were-green*`
-5. In pre-commit hook, inspect file modification time. Example:
+5. Observe `git status` _not_ showing timestamp file
+6. In pre-commit hook, inspect file modification time. Example:
 ```sh
 #!/bin/sh
 all_tests_were_recently_green() {
+    too_many_seconds_ago=$1
     thenstamp=$(date -r .when-all-tests-were-green-junit5 '+%s' 2>/dev/null || echo 0)
     nowstamp=$(date '+%s')
     secondsago=$(expr ${nowstamp} - ${thenstamp})
-    [ ${secondsago} -lt 30 ]
+    [ ${secondsago} -lt ${too_many_seconds_ago} ]
 }
-if all_tests_were_recently_green; then
+if all_tests_were_recently_green 30; then
     ./gradlew clean build -x test
 else
     ./gradlew clean build
 fi
 ```
+
+## More information
+
+See the
+[Greencently webpage](https://schmonz.com/software/greencently).