Babies. Horrible, noisy little sods. They cause drinking interuptus, bonking carefulus, money shortus, and similar afflictions.
Noise coming out of one end, shit out of the other, and they are delivered without the plumbing completed, whick means nappies(diapers to Americans)to wash, or worse, trees cut down to make paper ones to fill landfill or leave in beauty spots.

Then they grow into children!!! Useless for about 15 years.

Bah, Humbug.