If you're fast at replying to texts, you won't be able to wrap your head around those friends who seem to respond in three to five working days - sometimes for something that requires a yes or no answer.
Of course, we all lead busy lives, but arguably, messages often take little effort to respond to, so many people will not be able to make excuses for their pals who "unapologetically ignore your messages while posting selfies on social media."
And one woman was so fed up of her mates who were "notorious for doing this" that she took to Mumsnet to ask other people what they thought of those who take a while to reply to WhatsApp messages.
She fumed: "Some people are notorious for doing this. They will just unapologetically ignore your message while posting selfies on social media knowing full well you can see.
"I have my moments sometimes, as does everyone I think, although I'm certainly not a repeat offender."
She then gave an example, explaining that this person was the "reason for the thread."
She continued: "My friend and I got pregnant together (unplanned) we attend the same mother and baby class. I will text her 'Hi, are you going to class tomorrow?' something like that. Or, on the rare occasion, she'll text me something similar. I'll reply within a reasonable time and then...you guessed it...No reply, for days, and sometimes not at all.
"Then I'll see her at the next baby group and she'll be grinning like a Cheshire Cat like nothing has happened BUT the whole time she's out and about, posting selfies on social media etc.
"It really offends me and kind of irritates me too. (I would never be irritated or offended by this if it were a one-off but it happens consistently with this person). Maybe I should just stop texting her. Even though she's sweet in person. Which is why I'm confused.
"Lastly, not to sound controversial, I understand something a lot of people say to this is 'they're busy' or 'you don't know what's going on in their head'. It's a tricky one. Because I get that. But come on..."
In the comments, people understood that it was annoying, but said there's little you can do about it.
One wrote: "Some people are just s***e at replying to texts. As annoying as it can be, you are wasting energy getting upset about it.
"If it bothers you this much, save your time and energy for people who reply in the timeframe that you find acceptable."
Another commented: "I have had friendships fizzle out after I stopped doing the running, but then they weren't really friendships in that case. Stop bothering with her."
Someone else defended the woman, however, saying: "People are just busier and don't see this in the same priority as you. The worst thing about mobile phones is the expectation that you should be contactable at every moment."
What do you think? Let us know in the comments.