Why Sicilian is the best defence against e4?
So, why Sicilian is the best defence against e4? I think, answer is easy. Sicilian is very old defence, and it's the most difficult opening for both sides. So, it's very rich defence with many-many variations. In fact, Grand Masters often play c5 against e4. Sicilian is very popular opening, like Ruy Lopez or Queen's Gambit, or King's Indian Defence. Sicilian doesen't give full developement for Black. White develops faster. But it gives strong center with two central pawns. It's very good for attacking on Queenside, especially with moves g6 and Bg7, and a6-b5-b4. But White's Kingside is under attack too. And important moment it's better position for Black in endgame. Two bishops is very important in SIcilian defence. So, White shouldn't give up bishops for knights, especially dark-squared bishop for the Knight on f6. And Black should save both bishops or exchange them to other bishops.
Well, c5 is the best response to e4. Blunders, blunders again and again. White lost Queen, because of Knight fork. Maybe it will be better not to play 1.e4 and then 2.Bc4? If you don't know, how to play against Sicilian defence, don't play 1.e4. Play 1.d4 or something else. Newbies usually start with move e4, it's correct. But after 1...c5 White should play 2.Nf3 or 2.Nc3 (Open or Closed Sicilian). 2.f4 is common move too, but after 2...d5 position of Black is better. I like Grand Prix attack, it's very effective weapon against Black in any Sicilian variations, including Sicilian Dragon.