anti-climax

an event, conclusion, statement, etc., that is far less important, powerful, or striking than expected.

a descent in power, quality, dignity, etc.; a disappointing, weak, or inglorious conclusion: After serving as President, he may find life in retirement an anticlimax.

a noticeable or ludicrous descent from lofty ideas or expressions to banalities or commonplace remarks: We were amused by the anticlimax of the company's motto: “For God, for country, and for Acme Gasworks.”