UnderstatementA bit of tidying
Makes a huge mess sound like a small job.
After the birthday party, the house needed a bit of tidying.
Remember: Balloons, plates and cake everywhere: that's hours of work, not 'a bit'. The gap between words and reality makes the humour.
Short lessonSaying more or lessSometimes we stretch the truth, shrink it, or give things human feelings to make a point.