This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Quantum of Solace
Mathis' death scene was genuinely heartrending... until the Mood Whiplash hits.
The scene with the Bolivians crowding around a dripping tap attached to an empty tank... and seeing the last drop drip out.
Agent Field's death, especially when it is revealed that she was not even a field agent. She was so swept into Bond's world, wanted to do her part, but ended up being killed by enemy agents.
The theme tune, when you realize the lyrics are essentially a Madness Mantra for Bond. He is essentially counting the things that could be worse for him than a broken heart, due to Vesper's betrayal and subsequent death.