有的人是購物狂，有的人喜歡跟風購物，還有的人喜歡在別人購物時給人出主意，享受替人挑選物品的快感，這就是backseat buyer——后座購物者。

Backseat buyer is a person who gets excited over other people's future or current purchases. Backseat buyer enjoys helping other person choose stuff as much as buying something for himself/herself. Usually an enthusiastic shopper for themselves as well. It can also be used as an adjective and verb.

“后座購物者”會因為他人即將要購買或現在要購買東西而感到興奮。他們喜歡幫助別人挑選東西，對他們而言，幫別人購物和給自己購物一樣快樂。他們自己通常也是狂熱的購物者。“后座購物者”的動詞形式是“后座購物”，即backseat buying。

Example:

Whenever I think about getting a new gadget, my father goes backseat buyer.

每當我想買一個新玩意兒，我爸總是要做我的“后座購物者”。

If you don't stop backseat buying right now I'm going to smack you.

如果你再不馬上停止“后座購物”，我就要給你一巴掌了。

（中國日報網英語點津 陳丹妮）