I find it interesting that a simple change in punctuation can change the entire meaning and mood of a particular statement.  This is especially true for online conversations where it's otherwise difficult or impossible to convey mood and tone. 

I'm working on a project with a few other people where we were originally planning on meeting at 3pm on Friday afternoon, but one of the group members just pushed it back to 4.  Fridays aren't meant to be filled with work in the first place, and Friday afternoon's productivity diminishes exponentially with respect to time (I tried my hardest to make that sound as geeky as possible).  I just wrote an email to the group, and I said, "I'm hoping we can bang stuff out pretty quick because I'd like to get home at a decent time".  If that statement is followed by a period, it sounds like I'm stressed and hurried.  My true feelings are conveyed pretty well.  I don't want to be meeting on Friday afternoon, let alone on Friday at all.  I just want to go there, get the work done, and leave.  But in the email, I ended the sentence with an exclamation point, and it changed the mood entirely.  That was my plan.  I don't want to sound like a jerk, so I made the sentence seem light-hearted and somewhat humorous.  I've come across this fact several times in the past, and I'm always amazed at how I can convey truth and meaning, while at the same time sounding playful and agreeable.