Yes! DF is the one that catches me out all the time. I always read it as father in the first instance and I get more and more wide eyed reading through a post until I realise they're talking about a fiancéOr DF for either friend, fiancé or father. It adds to the confusion if they don’t specify which it is in a deliberately vague OP and you wonder why they’re shagging their dad. Or GP for either grandparent or doctor. Just bleeping type it all out, especially when the OP is 50 paragraphs long!
Agree at the very least, people could easily write "father (DF)" on the first occasion and then DF thereafter, and same for the rest of the D characters.