I've just been through a waking semi-nightmare.
With the ISP change, my mothers had to deal with updating e-mail address across a number of accounts. It's been weeks and the scheduling as finally sorted out for me to help deal with the various mailing lists and accounts from companies (adverts, news, sales papers, blah blah). All the time with me muttering how easy it should be for anyone to change such things, well guess what? I was blood wrong !!!!
Half of the mailing lists had to be unsubscribed and resubscribed, if there was a way to update it, the only practical means of doing so would be to e-mail the mailer program a 'help' message and see if it responds. Fluttering across the messages and the associated websites (where findable or Googlable) ranged from useless, to down right worthless. Some where actually pretty good, like the anti-virus data, figures they would make it simple ^_^. While others, it was just pitiful.... Hell on one -- belonging to a fairly well known company in it's category in fact. When submitting the form information, it through up an unhanded null pointer exception popup. Complete with a fucking stack trace and some paths data, for crying out fucking loud.... Showing any Joe blow submitting form data on the website, a bleeding stack trace!!!!
I know it takes a lot of work to make an attractive website, but geeze. How about actually making it a website worth visiting while ya at it fellas?