Sad that I've heard the majority of these.
Controller Johns
-This isn't my controller (so?)
-I was getting lag (lies)
-I'm using the Wiimote/Nunchuck (Your fault.)
-My buttons are sticky (DON'T EAT DONUTS BEFORE PLAYING)
-My Wavebird was 1/312 second behind (Frames are 1/60. It wouldn't matter)
-My controller came unplugged (Well who was holding it, genius?)
Character Johns
-You chose Marth/Meta-Knight/Wolf/Other high-tier character (And you didn't...why?)
-I was using Ike/Jigglypuff/Ganondorf/Other low-tier character (Your fault.)
-You were spamming moves (So spam your shield, moron)
-That character is so broken (This is only legitimate when facing Meta/Snake/G&W)
-I wasn't using my main (Your fault.)
-I chose random (Your fault.)
- I couldn't hit Captain Falcon's knee (That indicates failure on your part to setup properly)
Stage Johns
-I got gimped by the stage (EVERYONE gets gimped by FD. Get over it.)
-I didn't grab the ledge (Your fault.)
-This stage is cheap (Adapt.)
-This stage is too random (see above)
-Random gave us the worst stage (REALLY?!?!?!)
-You built the stage, so you had an advantage (Then don't suck as much.)
Player Johns
-It's your Wii (no, it's not)
-It's your disc (No, it's not.)
-I'm hungry (Your fault.)
-I'm tired (Your fault.)
-You cheated (YOU CAN'T CHEAT WITHOUT A CHEAT DEVICE.)
-I haven't played for a few days (Your fault.)
Misc. Johns
-Items are cheap (Then just let me use them and you play without 'em.)
-Your Final Smash is cheap (Thats why it's a Final Smash.)
-My Final Smash sucks (Your fault.)
Wi-Fi Johns
-Too much lag (Adapt.)
-My connections sucks (Your fault.)
-Your connection sucks (No, P2P connection sucks for everyone)
-We're in your Wi-Fi room (Your fault for joining.)
-We're using your rules (I was unaware I was credited with introducing 4 stock.)
-I couldn't see you so I couldn't use mind games (What?)