diff --git a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/DeathSoundEffects.java b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/DeathSoundEffects.java
index b4882ca..25fe1cf 100644
--- a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/DeathSoundEffects.java
+++ b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/DeathSoundEffects.java
@@ -59,10 +59,11 @@ public DeathSoundEffects() {
                     }
                 })
                 .filter(Objects::nonNull)
-                .collect(Collectors.collectingAndThen(Collectors.toList(), ImmutableList::copyOf));
-        if (this.death_sounds.isEmpty()) {
-            this.death_sounds.addAll(defaults.stream().map(Sound::valueOf).collect(Collectors.toList()));
-        }
+                .collect(Collectors.collectingAndThen(Collectors.toList(), list -> {
+                    if (list.isEmpty())
+                        list.addAll(defaults.stream().map(Sound::valueOf).collect(Collectors.toList()));
+                    return ImmutableList.copyOf(list);
+                }));
     }
 
     @Override
diff --git a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/ExplodeSoundEffects.java b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/ExplodeSoundEffects.java
index 486ae09..f96c43d 100644
--- a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/ExplodeSoundEffects.java
+++ b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/ExplodeSoundEffects.java
@@ -62,10 +62,11 @@ public ExplodeSoundEffects() {
                     }
                 })
                 .filter(Objects::nonNull)
-                .collect(Collectors.collectingAndThen(Collectors.toList(), ImmutableList::copyOf));
-        if (this.explode_sounds.isEmpty()) {
-            this.explode_sounds.addAll(defaults.stream().map(Sound::valueOf).collect(Collectors.toList()));
-        }
+                .collect(Collectors.collectingAndThen(Collectors.toList(), list -> {
+                    if (list.isEmpty())
+                        list.addAll(defaults.stream().map(Sound::valueOf).collect(Collectors.toList()));
+                    return ImmutableList.copyOf(list);
+                }));
     }
 
     @Override
diff --git a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/FireworkEffects.java b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/FireworkEffects.java
index f87587b..5dd199e 100644
--- a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/FireworkEffects.java
+++ b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/effects/FireworkEffects.java
@@ -1,5 +1,6 @@
 package me.xginko.pumpkinpvpreloaded.modules.effects;
 
+import com.google.common.collect.ImmutableList;
 import me.xginko.pumpkinpvpreloaded.PumpkinPVPReloaded;
 import me.xginko.pumpkinpvpreloaded.events.PostPumpkinExplodeEvent;
 import me.xginko.pumpkinpvpreloaded.events.PostPumpkinHeadEntityExplodeEvent;
@@ -102,7 +103,7 @@ public FireworkEffects() {
             }
         }
 
-        this.firework_effects = parsedFireworkEffects.stream().distinct().collect(Collectors.toList());
+        this.firework_effects = ImmutableList.copyOf(parsedFireworkEffects);
     }
 
     @Override
diff --git a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/mechanics/EnablePerWorld.java b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/mechanics/EnablePerWorld.java
index 026a92d..6db65db 100644
--- a/src/main/java/me/xginko/pumpkinpvpreloaded/modules/mechanics/EnablePerWorld.java
+++ b/src/main/java/me/xginko/pumpkinpvpreloaded/modules/mechanics/EnablePerWorld.java
@@ -1,5 +1,6 @@
 package me.xginko.pumpkinpvpreloaded.modules.mechanics;
 
+import com.google.common.collect.ImmutableSet;
 import me.xginko.pumpkinpvpreloaded.events.PrePumpkinExplodeEvent;
 import me.xginko.pumpkinpvpreloaded.modules.PumpkinPVPModule;
 import org.bukkit.event.EventHandler;
@@ -9,7 +10,6 @@
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Arrays;
-import java.util.HashSet;
 import java.util.Set;
 
 public class EnablePerWorld extends PumpkinPVPModule implements Listener {
@@ -22,7 +22,7 @@ public EnablePerWorld() {
                 "Add the names of the worlds you want this plugins features to be enabled in.");
         this.blacklist_mode = config.getBoolean(configPath + ".use-as-blacklist", false,
                 "Make it so that the plugin's features are disabled in the listed worlds.");
-        this.active_worlds = new HashSet<>(config.getList(configPath + ".worlds",
+        this.active_worlds = ImmutableSet.copyOf(config.getList(configPath + ".worlds",
                 Arrays.asList("world", "world_nether", "world_the_end")));
     }