Dialog 1 the flip side [ 反面 ]

Angela:Do you want to send our daughter to an international school?
Yukio:Hmm … I don't know.
Angela:Well, if she goes to one, her English will definitely improve.
Yukio:On the flip side, it'll cost a fortune.

Dialog 2 All good things must come to an end [ 全てのいいことには終わりがある ]

Yukio:How's your job going?
Angela:Great! The people in my section have such great personalities and are so much fun to work with.
Yukio:Glad to hear that. Enjoy it while you can because all good things must come to an end.
Angela:Hey, don't say that! You're bumming me out.