I actually find the European custom more logical. If we are having a casual conversation and I’m referring to a previous event that happened on the 14th, you c

I actually find the European custom more logical. If we are having a casual conversation and I’m referring to a previous event that happened on the 14th, you can assume from context that I mean the 14th of the current or previous month (eg the 14th of November as of the writing of this comment). If it isn’t the current month (+-1 based on context), I can instead specify that I meant the 14th of September and you will understand that I mean the 14th of September this current year (again +-1 by context). If I meant the 14th of September, 1987, I will say the whole date. But since most date-based conversations have an implied context, being able to simply truncate dates for brevity is useful. ISO 8601 is big-endian, European style is little-endian, and US-style is just kind of pointless.