Luffy wasn't discouraged. He knew Observation Haki wasn't invincible. Often, even when you knew an attack was coming, you still couldn't dodge it.
Why else would so many people use Iron Body to take powerful attacks head-on?
Luffy calmly shifted into Gear Second.
Seeing him, Enel laughed. "What's wrong? So tired you can barely stand?"
Luffy shook out his arms. "No. I'm getting ready to send you flying."
Luffy moved at a speed rivaling Soru. Enel smirked. Another right hook. How is this any different? One step back and a turn to the side, and I'll dodge it easily.
But before Enel could move, Luffy's fist struck him. In the end, his own arrogance had earned him a punch across the mouth.
"Damn it! He's faster!"
Enel turned into lightning and flashed away, landing at the bow. He watched Luffy warily, wary of his speed.
"You may be able to hit me," Enel said, "but when I turn into lightning, you can't keep up."
There was something Enel hadn't mentioned: the Ark was built mostly of gold. He could travel through it from one point to another in less than a second.
Crackle!
Enel flashed from the bow to Luffy's side and swept him off his feet with the Golden Staff. But apart from picking up some dust when he fell, Luffy was unharmed.
Enel paused to think. Then lightning poured from his hands, heating the Golden Staff to an extreme temperature. In an instant, he reshaped it.
"Thunder Metallurgy!"
The Golden Staff became the Golden Trident.
Enel pointed it at Luffy. "A staff might not hurt you, but a blade should!"
"Oh no," Luffy said in surprise. "He figured it out!"
Rubick: Old man. Subway. Phone!
"Luffy, keep Enel busy," Rubick said. "I'll go look for the Golden Bell."