diff --git a/mapper.go b/mapper.go
index 1b7fa4a..5a476c7 100644
--- a/mapper.go
+++ b/mapper.go
@@ -445,7 +445,7 @@ func mapDecoder(r *Registry) MapperFunc {
 			t := ctx.Scan.Pop()
 			// If decoding a flag, we need an argument.
 			if t.IsEOL() {
-				return fmt.Errorf("missing argument: expecting <key>=<value>%c...", mapsep)
+				return fmt.Errorf("missing argument: expecting \"<key>=<value>%c...\"", mapsep)
 			}
 			switch v := t.Value.(type) {
 			case string:
@@ -520,7 +520,7 @@ func sliceDecoder(r *Registry) MapperFunc {
 			t := ctx.Scan.Pop()
 			// If decoding a flag, we need an argument.
 			if t.IsEOL() {
-				return fmt.Errorf("missing argument: expecting <arg>%c...", sep)
+				return fmt.Errorf("missing argument: expecting \"<arg>%c...\"", sep)
 			}
 			switch v := t.Value.(type) {
 			case string: