1. Tell him that he basically is a copy of his brother.
2. Tell him it's weird he's taller, but still younger than Mario.
3. Imply that "Luigi's Mansion" is the only game about him...and it sucked.
4. Also tell him "Luigi's Mansion 2" will also suck.
5. Constantly remind him he stands in the shadow of Mario.
6. Chase him and yell: "SPAGHETTI!" over and over.
7. Tell him he would never be able to beat a level by himself.
8. Constantly remind him he's always player 2.
9. Tell him the colour green, which he wears, is a sign of jealousy.
10. Whenever he talks to you by your name, say: "That's Mama Luigi to you, Mario! *Weeze*"
11. Cling on him and repeat: "MAMA LUIGI!"
12. Remind him that he was never in Super Mario 64.
13. Tell him over and over that his surname is Mario's name.
14. Run over to him, say: "Gay Luigi?" then run off again.
15. Say to him he's only strong enough to beat Bowser Jr.
16. Constantly remind him that he looked so wimpy when walking in a dark room in Luigi's Mansion.
17. Tell him Daisy will never like him.
18. Buy a Mario plushie and throw it at him over and over. When the sweet, kind Luigi finally gets mad at you, cry and say: "And you're supposed to be my idol, Luigi!"
19. Tell him that his final smash is so lame in Super Smash Bros Brawl.
20. Remind him that Mario got the glory when Luigi knocked all the koopas out of the way in a Super Mario Bros Intro.
21. Tell him that Mario always gets the glory, no matter how much he has done to help saving Peach.
22. Shave off Luigi's smexy mustache when he's asleep. He won't look as handsome the next day.
23. Dye his clothes pink. Then he would definitely look like "Gay Luigi".
24. Tell him Mr. L is way sexier than him.
25. Record on a tape recorder that says: "Suku suku! Jabbo jabbo! (Elvin Gadd's voice)" and press the repeat button. Put it in his room when he's trying to sleep. Find him the next morning to see the results.
26. Tell him he needs to eat more, wear red etc. so he could look just like Mario.
27. Tell him Waluigi is more awesome than him.
28. Carry a Luigi plushie around. Then you nuzzle it in to his head constantly and say: "LUIGI-CHAN WUUUVES U!!"
29. Find his diary, copy each page and send them to everyone in Mushroom Kingdom.
30. Say to him Nintendo will never give him as much attention as Mario.
31. Dye his clothes black, wear them and become emo. Tell Mario you hate him and the whole world. If Mario asks you why, tell him he can stick that question up his ass.
32. Ask him to tell you a story when you go to bed. When he tries to come up with something, say: "Oh! Oh! Tell me the story when Luigi gets pwned by Bowser!"
33. Tell him the 1UP mushrooms runs away from him just because he's Luigi.
34. When he sleeps, scream in to his ear: "Lotsa spaghetti! Lotsa spaghetti! SPAAAAAGHEEEEEETTIIIIIII!"
35. Poke on him several times. If you FINALLY gets him to get a little pissed, him telling you to stop, poke on his nose. See if you can poke him 'til he finally chases you with a pitchfork.
36. Take his hat, and put it on your head. Then run around like an idiot and yell: "Hey, look everyone! I'm LUIGI! AND IMMA COPY OF MAH BROTHA!"
37. Ask him if you can draw a portrait of him. If he says yes, make the portrait look just like Weegie, and then show it to him. If he refuses to get a portrait, cry, and say that you only wanted to draw your hero.
38. Start to hug him. ALL the time. When he asks you why you do that, reply: "ME WUUVES U. ME NOT LETTING GO." Don't let go, no matter how hard he tries to (when you've been stucked to him for a day or two, that is).
39. Buy a toad plushie, wave it in front of his face and repeat: "Thank you, Mario. But the princess is in another castle." with Toad's coughy voice. The thing that will disturb him is that he isn't Mario.
40. Dress just like Daisy, cling on him and scream: "MARRY MEEEH, HAWT STUFF!"