Why is there have a maximum limit on how many characters you can put in a post?

It's extremely annoying (in the last week I ran into it at least half a dozen times

) and quite frankly I don't see what possible advantage it could have

(I could understand a minumum number of characters but a maximum?)
Markos, could you please either abolish this limit or raise it to something like 30,000 characters? I would be most grateful; 20,000 characters just isn't enough if you're working with HTML-tables or large summaries or overviews (see FE my threads in the Civ3-Civilizations forum)...
(Alternatively, take a look at Gramphos's suggestion
here. It's only helps part of the time but it does help)
Edit: Aaarg, could you do something about the ridiculous order in which the smilies are processed too?