What's the matter with these length limits on text areas? As I see it, usability mistake is that these limits exist, not that they are not clearly displayed. I

What's the matter with these length limits on text areas? As I see it, usability mistake is that these limits exist, not that they are not clearly displayed. It is probably wise to have some internal limit of size of text saved somewhere, but such limit can well be something like 100k, which normal user has no real chance of exceeding and thus you don't have to present it to user in any way.