This week I'm going to look at what makes a deck casual - at least in my narrow-minded view. I don't think it has anything to do w/ the colour or even the cards; it has to do w/ how you play the cards. There's nothing wrong w/ a little burn - but not when it's aimed at lifetotals. If you want to counter everything expect to be attacked - a LOT! Since the most popular 'casual' format is multiplayer you can't just think about winning against one deck. You have to be ready to beat ALL of the decks - without getting yourself killed in the process. So, this could lead to many schools of thought:
A good offense is the best defense: get big critters out FAST and attack, attack, attack! try to get everyone's life totals to zero before they can retaliate - this method rarely works as the other players will eventually gang up on you.
A good defense is the best offense: summon lots of defensive critters (walls, Singing Trees, Veteran Bodiguards), use defensive enchantments (Island Sanctuary, Orim's Prayer, etc) or use defensive artifacts (Forcefield, Winter Orb, Ivory Tower, etc) while you build up your eventual force to clobber everyone - this strategy can go wrong if people catch on to what you're doing and gang up on you.
Use 'Diplomatic' cards: Want to make four or five friends? Put down a Mana Flare or Howling Mine. Want to watch real fun? Put down Zur's Weirding - great in games w/ lots of players w/ lots of life. These cards will lower players' urge to kill you while you prepare for a kill of your own.
Draw Go: load your deck up w/ every counterspell known to man to keep everyone from doing anything. This strategy will get you killed. You won't be able to counter everything and everyone remembers you countering their other spells and will come after you relentlessly. Some good ways to prevent death is to use other annoying cards like Treachery, Bribery, Control Magic - again, cards that will get you killed.
Red Burn: Red's a great creature colour. It has Goblins and Dragons and Giants (oh my!), but if you're feeling really suicidal make a deck of nothing but burn cards. You can use little burn spells (Lightning Bolt, Incinerate, Chain Lightning, Fireblast) and the big X spells (Fireball, Disinitigrate, Blase (that's not a typo), etc). If you're lucky you'll torch everyone out of existence before they've smashed you flat first. Again, not a very fund deck to play.
Combo decks: Yes, you can use combo decks in multiplayer. They usually take more then three turns to setup (usually a LOT more), but they can give you the thrill of beating all players. Some great ones include Zuron Orb/Channel/Hurricane, or variants of Fruity Pebbles. A thousand laughs and a way to expect to be dead on turn two or three of the next game.
Now, a lot of these decks may not be considered casual - or you may see them every week when you play, but as long as everyone's having fun any deck can be considered 'casual'.
"...except that channel/hurricane deck! I hate that one..."