diff --git a/at.go b/at.go
index ebb5676..275e3c4 100644
--- a/at.go
+++ b/at.go
@@ -65,8 +65,8 @@ func (a *atMonitor) Run(c *irc.Client, done chan bool) {
 
 			current := atHS.UserListZWS()
 
-			arrived := listSubstract(current, a.previousUserList)
-			left := listSubstract(a.previousUserList, current)
+			arrived := listSubtract(current, a.previousUserList)
+			left := listSubtract(a.previousUserList, current)
 
 			if len(arrived) > 0 {
 				diffText = fmt.Sprint(" +", arrived)
diff --git a/helpers.go b/helpers.go
index 4f8bda9..56159de 100644
--- a/helpers.go
+++ b/helpers.go
@@ -7,7 +7,7 @@ import (
 	"time"
 )
 
-func listSubstract(a, b []string) (ret []string) {
+func listSubtract(a, b []string) (ret []string) {
 	mb := make(map[string]bool, len(b))
 
 	for _, x := range b {