I hate it, I hate it when that happens! Either when someone is trying to send me a message or me not being able to send one because the mailbox is full. What's worse is that when I clear messages out, the message I wasn't able to receive doesn't come back. I hate to be a digital hoarder, but I like keeping all of my messages. Luckily I have my inbox attached to my gmail, but I do end up missing out on a lot of my sent messages.