What does DHL mean by end of day delivery?

Okay, so DHL's "end of day delivery"... what does that even mean, right? Ugh, it's supposed to be by 6 PM, that's when they officially close shop, I think. But honestly? It's a total crapshoot. Like, will it actually show up then? Later? Or sometimes – and this is the really crazy part – even earlier?! I swear, it's happened to me before!

It's just such a vague window, isn't it? Like, "end of day" could be anything. You'd think, with all the technology they have these days, they could give you a tighter timeframe. You know?

I remember this one time, I was waiting for a super important document to be delivered. "End of day," they said. So, I was basically glued to the window all afternoon, missing calls, not even able to pop out to the grocery store! It was agonizing! And guess what? It finally showed up at like, 7:30 PM! I was furious, not to mention starving!

Honestly, all I'm saying is that a little more precision would be amazing. It makes planning my whole day around waiting for a delivery a total, utter nightmare. I mean, come on, DHL, throw us a bone here, yeah? Just give us a ballpark, something a little more specific! Please?!