Got into a big online argument about this last week. People kept recommending those '20 spiciest moments' compilations that just list chapters with zero context, which drives me nuts. If I want pure heat I'll read erotica. What makes 'icebreaker' scenes work is how they're woven into character arcs - the payoff comes from tension built over pages, not just the act itself.
For me, 'A Court of Silver Flames' nails it. Chapter 42 is the notorious 'wall scene,' but reading it cold would be meaningless. The real weight comes from chapters 19, 31, and 38 establishing Nesta's self-loathing and Cassian's patient unraveling of her armor. The physical intensity directly mirrors her emotional breakthrough. Same with 'The Love Hypothesis' chapters 14 and 15 - the lab scene works because it follows Olive's hilarious internal panic about faking a relationship, making the sudden real intimacy both hot and narratively earned.
I tend to skip lists that don't mention what happens three chapters before and after. A good spicy chapter should feel inevitable, not inserted.