How we cite our quotes: (Chapter.Paragraph)
Quote #7
He wondered if he'd lived in a city like this before, and if he had, how he could possibly have forgotten the splendor of it all. (24.35)
When Thomas sees Denver, he's amazed and can't believe that he has no memory of any kind of city like Denver. It's pretty depressing thinking about how Thomas can't remember grand and beautiful spectacles that he once saw in his past life.
Quote #8
And a memory bubbled up in Thomas. Something about a fail-safe programmed into his implant to prevent it from being removed. (27.7)
Don't you just hate it when you remember something right when it's too late? This happens to Thomas all the time, and in this case, his mind goes under the control of WICKED right when he remembers that they programmed a fail-safe into his memory-implant.
Quote #9
It's all there for the taking. For the remembering. But then he changes his mind, turns his back on it all. The past is the past. There is only the future now. (28.12)
This mindset is ultimately what propels Thomas forward: he's finally able to look into the future without thinking about the past. If he were to dwell in the past, there would be the chance of him changing his mind about WICKED.