It is really easy to get the order of magnitude wrong on a number in code. I had settled into the habit of carefully counting my digits to make sure it was right until one of my co-workers pointed out a neat feature of ruby.
Ruby allows underscores to be inserted into numbers between any two digits. The underscores are purely cosmetic and do not affect the value of the number. This feature allows a developer to use underscores as an accountant might use commas.
3193490646 # standard representation of a number in ruby 3_193_490_646 # same value, much more readable
One less excuse for order of magnitude errors when using ruby.
Thanks to Dallas Reedy for introducing me to this awesome feature of Ruby