diff --git a/defaults/system.nix b/defaults/system.nix
index 6811152..e37b795 100644
--- a/defaults/system.nix
+++ b/defaults/system.nix
@@ -52,6 +52,9 @@ in
       tmpfsHugeMemoryPages = "within_size";
     };
 
+    # this is useful not only for having a user named "tmp"
+    # but also if any user wants to use a temporary directory,
+    # it's much nicer than /tmp because it isn't filled with system files
     fileSystems."/home/tmp" = lib.mkDefault {
       fsType = "tmpfs";