Funny: Castle of Shikigami aka: Shikigami No Shiro
The third game
A lot of the conversations in CoS III are this, whenever it's not being serious. While it's more or less 50-50 in most single character scenarios, a LOT of the scenarios in Dramatic Change Mode are notable for cranking the Silliness SwitchUp to Eleven. In some extreme cases, even the end-stage bosses (most of which are fairly calm or demure) can fall prey to the stupidity of the conversation or feel embarrased by it. For example, in the Kohtaro-Reika scenario, as a result of Reika's rambling:
Tsukiko: "Um, hello? I'm the last boss here. Please don't ignore me."
And when they get to the Final Boss, Tsukiko, who's the only who doesn't express being creeped out by their antics (or gets roped into it, like Kagachi), the brief dialogue between them and Roger is pure gold.