I've always had bushy eyebrows. A few years ago I went to a barber and after the cut was asked if I wanted them trimmed - I said sure. Every month or so since I've trimmed them down to 5mm.
It makes them less heavy and look more youthful. I recently purchased a new beard trimmer - it's really rather good - but unlike my old one, it only has even numbers.
A few minutes later I was trimming my beard line on 0.4mm. Whilst doing so, I came to realise I'll have to pick a new length to trim my eyebrows.
I reflected for several moments and decided that 6mm would do. Beard line done. Next I thought, "hey, I'll try it on my eyebrows now". Now, smart me sees the 6 in 0.
6mm, ignores the fact there's a 0 in front of it and, without hesitation, proceeds to trim my eyebrow.
I now have 1 eyebrow :)
TL;DR: Great new beard trimmer. Trimmed my eyebrow off really nicely.
Edit: [Notice the end](http://imgur.com/a/VbbgS). Like a relic of a lost civilisation.