anticlimax
/ˌæntɪˈklaɪmæks; ˌæntɪ`klaɪmæks/ n
disappointing end to a series of events which had seemed likely to become more interesting, exciting or impressive 令人扫兴的结局
The holiday itself was rather an anticlimax after all the excitement of planning it. 尽管计划度假时兴致勃勃, 而到头来假日本身却颇为扫兴.