When travelling, and when I can, I download my Yahoo! webmail to Windows Mail ( ex- Outlook expresss ) on a laptop, then read at leisure offline.
Initially all the mail is downloaded, then when the last message is received "someone" - Yahoo! or Windows Mail ? - starts to remove all the junk, either those that they know is Spam, or those whose names I have previously marked as Junk, so I am more or less only left with those of interest.
Yesterday I noticed an e-mail from a long past friend in the list, but then it totally disappeared, not in deleted mail, not in junk mail, not in Spam - nowhere.
Fortunately it was still on the server so I was able to read it next time I was able to go Online, but I might never have know it had been sent to that Great Rubbish Bin In The Sky.
Life was easier before computers !