When we describe the products we are making, more often than not, and too often, we say 'and then it does this'. We should catch ourselves when we do this because it's a sure sign that we have just forgotten, even momentarily, who the product is for. It's not for us, it's not for 'it', it's for them. The customer. Or user if you want to be vanilla.
Case in point.
In outlook or Mac Mail, if you are in your 'sent' items and you click reply, it does what a program logically does which is reply to the person who sent the mail, which in sent mail just happens to be you.
"Hang on, here is an email, you hit reply, it should reply it to who sent it. Surely."
Don't focus on what happened, focus on why happened. Why did they click reply? To resend the email they have right now to themselves? No, never, I can't think of a reason to do that.
They do it to resend the email to the same person with or without new information.
Gmail gets this right. In sent mail if you hit reply, it will put the person or persons you sent it to in the to box. So simple.
Each step of the way, think about why they did something, or more importantly, think about what they want to do and why, then create the action. Maybe the button should change in 'Sent Items' to say [Resend].
Dough, Ray, Them!