Examples:

• If I don't, "thumbs down."
• Two thumbs down to the serpent who led Lester astray!
• Dreadful, thumbs down, embarrassing—thank you, these are great answers, but they're answers to a different question.
• Moore's law made computing cheap; so cheap we can weigh the life of an individual insect and decide thumbs up or thumbs down.
• There are such large areas of doubt and such major errors that, in practice, the Court of Auditors is giving the thumbs down to quite crucial areas of the EU budget.
• The variety of flavors offered is truly priceless, really very good, useful to please all palates; shipment we say thumbs down view of the long wait for delivery.