diff --git a/.rubocop.yml b/.rubocop.yml
index a62b89e..9adcfbd 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -18,3 +18,9 @@ Layout/ElseAlignment:
   Enabled: false
 Layout/IndentationWidth:
   Enabled: false
+Metrics/AbcSize:
+  Max: 30
+Metrics/PerceivedComplexity:
+  Max: 15
+Metrics/CyclomaticComplexity:
+  Max: 15
diff --git a/lib/obk.rb b/lib/obk.rb
index aa127d2..dda7d32 100644
--- a/lib/obk.rb
+++ b/lib/obk.rb
@@ -40,12 +40,21 @@ def initialize(origin, pause: 1000)
   def method_missing(*args)
     left = @pause - (Time.now - @latest)
     sleep left if left.positive?
-    result = if block_given?
-      @origin.__send__(*args) do |*a|
-        yield(*a)
+    mtd = args.shift
+    result = if @origin.respond_to?(mtd)
+      params = @origin.method(mtd).parameters
+      reqs = params.count { |p| p[0] == :req }
+      if params.any? { |p| p[0] == :key } && args.size > reqs
+        @origin.__send__(mtd, *args[0...-1], **args.last) do |*a|
+          yield(*a) if block_given?
+        end
+      else
+        @origin.__send__(mtd, *args) do |*a|
+          yield(*a) if block_given?
+        end
       end
     else
-      @origin.__send__(*args)
+      super
     end
     @latest = Time.now
     result
diff --git a/test/test_obk.rb b/test/test_obk.rb
index e988008..7e6a3d8 100644
--- a/test/test_obk.rb
+++ b/test/test_obk.rb
@@ -36,11 +36,32 @@ def test_simple
     def obj.read(foo)
       foo
     end
-    obj = Obk.new(obj, pause: 1000)
+    obj = Obk.new(obj, pause: 100)
     start = Time.now
     assert_equal(42, obj.read(42))
     assert_equal(42, obj.read(42))
     stop = Time.now
-    assert(stop - start > 1)
+    assert(stop - start > 0.1)
+  end
+
+  def test_works_with_optional_arguments
+    obj = Object.new
+    def obj.foo(first, _second, ext1: 'a', ext2: 'b')
+      first + ext1 + ext2
+    end
+    synced = Obk.new(obj, pause: 10)
+    assert_equal('.xy', synced.foo('.', {}, ext1: 'x', ext2: 'y'))
+    assert_equal('fzb', synced.foo('f', {}, ext1: 'z'))
+    assert_equal('-ab', synced.foo('-', {}))
+  end
+
+  def test_works_with_default_value
+    obj = Object.new
+    def obj.foo(first, second = 42)
+      first + second
+    end
+    synced = Obk.new(obj, pause: 10)
+    assert_equal(15, synced.foo(7, 8))
+    assert_equal(43, synced.foo(1))
   end
 end