Here, if you hear: "I give you my word; I'll be there before the weekend." You should have asked: "Which weekend?" It's important to pin down the speaker. Not only could it be the next weekend, it could be months from then. However, the person will appear.
Here, if you hear: "I'll be there shortly." You might have to wait a few weeks and maybe then it won't happen. It depends on how many other things appear before your interests become a priority.
Here, if you hear: "I'll be there directly." Chances are you'll see that person by the end of the day. Maybe. At least, he won't make any side trips first – unless they are directly on the way.
Here, time is not specific. This evening could be anytime after lunch but before midnight.
"Come for dinner." You invite your neighbor.
"Oh, we'd love to come."
"Good. Come over after work. Around 6:30."
You work for hours preparing something delicious. The appointed hour arrives and no one comes. The next day you ask your neighbor if everything is okay. Since they didn't come to dinner, you can't conceive of anything short of an illness keeping them away or from at least sending a message.
"Oh, we didn't think we'd come last night, maybe tonight?"
It's not being rude. It's just a different understanding of time, of eating habits, of meal preparation. Why would anyone make a special meal for neighbors?
"We'll come tonight."
And they do. Around 9 pm. After you've given up, put everything away again and helped yourself to the rum. They arrive with their three children and a Spanish speaking cousin from Honduras. And they're hungry.
The word is good; the timing is a little off.