When reading his paragraph I realized his, and all of his companion's mistakes. He mentioned he had used the same deck to oppose several foes several times. I would challange him once with my "Twist" deck. My "Twist" deck uses all colors, has no theme and seems totally worthless at first glance. But it has been able to defeat most foes within 3-4 rounds. The key is cards that let you play more than 1 land per round and creatures that are strong, almost no cost, and expendable.
If the deck was composed of Scale Wurms (7/6) I would lose due to huge casting costs. Sea Singer and several assorted elves prove well in doing up to 5 damage per turn. Though the seasinger is useless at first glance, by the time your opponent gets out one creature it's already yours. Control Magics help keep enemy hordes under your command.
Anyway back to the topic, had I played this person and he had defeated my "Twist" deck, I would've adjusted it according to his deck to use all of his things against him, and come back at him.
So continually make minor adjustments to your decks, or build new ones!
This is just a little advice if you're playing a white deck. White decks can heal, but only the most focused of players can pack some damage quick. If you're not a super-player but want to look like one some advice is pack your deck with Circle Of Protections. There are White, Black, Red, Green, Blue, Artifacts and Shadow Circle of Protections. With this quick cover you can fend off attacks while waiting to draw something powerful. I find that a very popular color is black, it can pack damage well, even with a mediocre player. If you're a well-crafted player and get whalloped by a black-playing mediocre here's some advice: Angry Mob. Angry Mob is a */* that's power and toughness is equal to number of swamps enemy controls. I find most new players, if playing all black cram up to 25 swamps in a deck. With Angry Mob's trample, and a Black Ward on it, it'll be unstoppable.
If you play black and have trouble stopping that 7/6 Scaled Wurm, or that 10/10 Sengir Vampire, just listen to this. Ram as many 1/1 regeneratables as you can in a deck. Also throw in a pestilence, Drain Life and a few Corrupt. I find most decks get pretty messed up when Pestilence is destroying their once mighty army and your army just stumbles back out of the grave. Drain Life and Corrupt stop most people in their tracks if you save until you have lots of mana out. A Wall of Shadows also usually annoys bulked up baddies without trample.
Then again you could be playing a blue deck and be beyond angry that your characters could not stop gerbil feces. Blue is infact one of my favorite colors. Loaded with Unsummons, Controls Magics and Sea Singers, your opponent will be annoyed beyond belief. Having trouble with Island Walkers? Magical Hack, give them Mountainwalk, problem solved. And if they've got an Artifact giving you a problem, Control Artifact works. And if you are just one sick little paranoid person like me: Wandering Eye, take a gander at their hand. Urza's Glasses is an Artifact, but, hey you can play it.
Green, what a color. Green has many creatures that add two green to your mana pool, pick one, they're excellent. Green plays several Elementals but they're usually not very good. And if you can defend yourself long enough Wurms make extraordinary defense and offense. Green's Wall of Brambles is a favorite of mine, being a defender with regenerate, cheap. Green's Regeneration card helps protect my precious Wurms. My favorite. If you are playing against a blue deck, wait until everything is almost over, Tsunami (destroys all islands) then target creatures, they'll be defenseless. Having trouble with flying creatures? Faeries with Regeneration on them.
Red decks are amazing. Many cheap goblins combined with several Goblin Grenades go a long way. While your goblins wreak havoc on the enemy's front lines, you can sit back, Lava Burst and Meteor shower everything. Red's brute force is rather hard to harness and direct, so there's not much here, when I further enter the color I will post more.