Help the Reader's Journey to Understanding

We've all been there, busy, harassed and harried. You think to yourself: 'just one more message'. You look and see:

"I can't do the thing on the Tuesday, let's move it to the 19th."

What?

When I get messages like this, my blood runs a little cold. I go into panic mode. What in the world are they talking about?

In my mind I start trying to do pattern matching on 'Tuesday'. Nope. 'thing'? Ugh...nothing. Heavy sigh.

At this point, I do a calculation: is it worth trying further to decode this person's email?

If the answer is 'no', then I'll either ignore the message, answer with a "What?", or if I'm feeling particularly devilish "No, the whatsit gets in the way. Let's do it the other day...or even better yet, after the doohickey is done."

If the answer is 'yes', I dig in, crank up another couple of brain cells (dropping what they were working on), and start trying to think of all the times this person has referred to a 'thing'. Is it /this/ Tuesday? The one after that? The first Tuesday after Easter?

I do another calculation...this person has now cost me a fair bit of brain energy. I'm starting to get ever-so-slightly resentful. /Should/ I even know what they were on about?

A 'yes' means that I have to focus completely on the message. Usually, however, the answer is 'no'. Unfortunately, if I've gotten to this level of calculation, I'm starting to get mildly annoyed as well.

Why not be a fraction more explicit? No room for wiggling, no doubt, and no misunderstanding:

"I can't attend the code review on Tuesday the 17th at 11am. Let's move it to the 19th at 10am."

Much better. I know exactly what they're talking about, I can pull it up in my calendar immediately, it only takes a second to give an answer, and I'm ready to work on whatever it is.

Please consider the journey your audience will have to travel to understand your message! It doesn't matter whether it's written on paper, an email, or sent as a text or even just a direct message. 

What hoops will the reader have to jump through to understand what you mean?