It's not really hotmail's fault
I everyone should look through the titles in the junk mail folder in ANY mail system, after all it tells you how many messages there are in the folder so you know they're in there. I very rarely get non junk mail in my hotmail junk box but if I do I just highlight it an click on the 'not junk' button. That way the next time a message comes from that person it goes into the in-box.
If you are using an organization's E-Mail system then it is possible that, if they send out news letters/flyers etc, then someone has moved it to the junk file and when it's auto-deleted after 10 days the address will be added to the list of spammers at Hotmail and all mail from them will be treated as spam.