One of the worst feelings in the world is when a judge issues you a game loss that you could have prevented. I still remember the first time it happened to me. It was State Champs-Sealed (Ravnica Block) and I had turned in a 39 card deck list. I was so disappointed with myself. In my defense my pool was terrible and I had a hard time building a deck. I had all the mana-fixing, but no actual win-cons. Anyways; I should have been a little bit quicker when building my deck, so I had time to double/triple check my decklist. Most of the time, Game Losses (GL) can be prevented, so I will go through what to watch out for at Competitive REL events.