flatter有滥用溢美之词; 奉承; 讨好; 谄媚。flatter yourself 自作多情。

【例句】
Don't flatter yourself, you could be wrong next time.
别太自以为是了，你可能下次就是错的了。

Hey, don't flatter yourself. He asked some friends to dinner because he wants to make friends with your sister.
嘿，别自吹自擂了。他请了一些朋友吃饭，因为他想和你妹妹交朋友。