I ate a clock yesterday. It was so time-consuming.

Behind the Groan

Consuming Time Literally

A time-consuming activity normally requires a long while to finish. Eating a clock makes the phrase literal because the meal itself consists of something that measures time. The absurd first sentence should be delivered without explanation, as though yesterday's menu was perfectly ordinary. Pause before the second sentence, then keep “time-consuming” together as one familiar expression. Listeners first hear a complaint about duration and then recognize that the speaker has supposedly consumed time in a much more direct way.