diff --git a/druid/component.lua b/druid/component.lua
index 9b79b88..ba0d834 100644
--- a/druid/component.lua
+++ b/druid/component.lua
@@ -162,9 +162,11 @@ end
 -- by `Component.static.create`
 -- @function component:initialize
 -- @tparam string name Component name
--- @tparam table interest List of component's interest
+-- @tparam[opt={}] table interest List of component's interest
 -- @local
 function Component.initialize(self, name, interest)
+	interest = interest or {}
+
 	self._component = {
 		name = name,
 		interest = interest
@@ -176,7 +178,7 @@ end
 -- druid component.
 -- @function Component.create
 -- @tparam string name Component name
--- @tparam table interest List of component's interest
+-- @tparam[opt={}] table interest List of component's interest
 function Component.static.create(name, interest)
 	-- Yea, inheritance here
 	local new_class = class(name, Component)
diff --git a/druid/const.lua b/druid/const.lua
index 1db17e2..83ed071 100644
--- a/druid/const.lua
+++ b/druid/const.lua
@@ -37,6 +37,19 @@ M.ON_LAYOUT_CHANGE = hash("on_layout_change")
 M.ON_LANGUAGE_CHANGE = hash("on_language_change")
 
 
+M.ALL_INTERESTS = {
+	M.ALL,
+	M.ON_INPUT,
+	M.ON_UPDATE,
+	M.ON_MESSAGE,
+	M.ON_FOCUS_LOST,
+	M.ON_INPUT_HIGH,
+	M.ON_FOCUS_GAINED,
+	M.ON_LAYOUT_CHANGE,
+	M.ON_LANGUAGE_CHANGE,
+}
+
+
 M.PIVOTS = {
 	[gui.PIVOT_CENTER] = vmath.vector3(0),
 	[gui.PIVOT_N] = vmath.vector3(0, 0.5, 0),
diff --git a/druid/system/druid_instance.lua b/druid/system/druid_instance.lua
index bd02e44..93782d7 100644
--- a/druid/system/druid_instance.lua
+++ b/druid/system/druid_instance.lua
@@ -63,21 +63,15 @@ local function create(self, instance_class)
 	local instance = instance_class()
 	instance:setup_component(self._context, self._style)
 
-	self.components[const.ALL] = self.components[const.ALL] or {}
 	table.insert(self.components[const.ALL], instance)
 
 	local register_to = instance:get_interests()
-	if register_to then
-		for i = 1, #register_to do
-			local interest = register_to[i]
-			if not self.components[interest] then
-				self.components[interest] = {}
-			end
-			table.insert(self.components[interest], instance)
+	for i = 1, #register_to do
+		local interest = register_to[i]
+		table.insert(self.components[interest], instance)
 
-			if const.UI_INPUT[interest] then
-				input_init(self)
-			end
+		if const.UI_INPUT[interest] then
+			input_init(self)
 		end
 	end
 
@@ -86,7 +80,7 @@ end
 
 
 local function process_input(action_id, action, components, is_input_consumed)
-	if not components then
+	if #components == 0 then
 		return is_input_consumed
 	end
 
@@ -130,7 +124,11 @@ function Druid.initialize(self, context, style)
 	self._style = style or settings.default_style
 	self._deleted = false
 	self.url = msg.url()
+
 	self.components = {}
+	for i = 1, #const.ALL_INTERESTS do
+		self.components[const.ALL_INTERESTS[i]] = {}
+	end
 end
 
 
@@ -182,14 +180,12 @@ function Druid.remove(self, component)
 	end
 
 	local interests = component:get_interests()
-	if interests then
-		for i = 1, #interests do
-			local interest = interests[i]
-			local components = self.components[interest]
-			for j = #components, 1, -1 do
-				if components[j] == component then
-					table.remove(components, j)
-				end
+	for i = 1, #interests do
+		local interest = interests[i]
+		local components = self.components[interest]
+		for j = #components, 1, -1 do
+			if components[j] == component then
+				table.remove(components, j)
 			end
 		end
 	end
@@ -201,10 +197,8 @@ end
 -- @tparam number dt Delta time
 function Druid.update(self, dt)
 	local components = self.components[const.ON_UPDATE]
-	if components then
-		for i = 1, #components do
-			components[i]:update(dt)
-		end
+	for i = 1, #components do
+		components[i]:update(dt)
 	end
 end
 
@@ -233,6 +227,7 @@ end
 -- @tparam hash sender Sender from on_message
 function Druid.on_message(self, message_id, message, sender)
 	local specific_ui_message = const.SPECIFIC_UI_MESSAGES[message_id]
+
 	if specific_ui_message then
 		local components = self.components[message_id]
 		if components then
@@ -243,10 +238,8 @@ function Druid.on_message(self, message_id, message, sender)
 		end
 	else
 		local components = self.components[const.ON_MESSAGE]
-		if components then
-			for i = 1, #components do
-				components[i]:on_message(message_id, message, sender)
-			end
+		for i = 1, #components do
+			components[i]:on_message(message_id, message, sender)
 		end
 	end
 end
@@ -257,10 +250,8 @@ end
 -- @function druid:on_focus_lost
 function Druid.on_focus_lost(self)
 	local components = self.components[const.ON_FOCUS_LOST]
-	if components then
-		for i = 1, #components do
-			components[i]:on_focus_lost()
-		end
+	for i = 1, #components do
+		components[i]:on_focus_lost()
 	end
 end
 
@@ -270,10 +261,8 @@ end
 -- @function druid:on_focus_gained
 function Druid.on_focus_gained(self)
 	local components = self.components[const.ON_FOCUS_GAINED]
-	if components then
-		for i = 1, #components do
-			components[i]:on_focus_gained()
-		end
+	for i = 1, #components do
+		components[i]:on_focus_gained()
 	end
 end
 
@@ -283,10 +272,8 @@ end
 -- @function druid:on_layout_change
 function Druid.on_layout_change(self)
 	local components = self.components[const.ON_LAYOUT_CHANGE]
-	if components then
-		for i = 1, #components do
-			components[i]:on_layout_change()
-		end
+	for i = 1, #components do
+		components[i]:on_layout_change()
 	end
 end
 
@@ -297,10 +284,8 @@ end
 -- @function druid.on_language_change
 function Druid.on_language_change(self)
 	local components = self.components[const.ON_LANGUAGE_CHANGE]
-	if components then
-		for i = 1, #components do
-			components[i]:on_language_change()
-		end
+	for i = 1, #components do
+		components[i]:on_language_change()
 	end
 end