I did fly LH F alone, on the 747. I had two FAs just for me, and of course the purser stopped by to introduce herself and let me know that I she'd be at my service should I need her.
The FA did everything just like if she had a full cabin to attend to -- I was impressed. She setup the carts, the flowers, the linen, everything -- except that the carts stayed by my seat 🙂 She was sad food would go to waste so she offered to give me the complete 'mini-towers' of appetizers and desserts. So I ended up eating three appetizers and desserts... needless to say I wasn't hungry for breakfast later.
It was a very enjoyable experience, and it wasn't too ackward because it was a night flight -- after dinner I just went to bed and didn't bother anyone until breakfast!
The only thing that felt a bit weird was seeing wine opened just for me -- I didn't want to drink too much so I wasn't comfortable sampling wines, although I would have loved to.
Upon landing the FA lead me to the bus downstairs--a long articulated bus just for myself. I arrived at the F lounge and realized the FA hadn't returned my BP, so they didn't want to let me in :/ I insisted that they look me up and after the agent did find me in the manifest, she did finally agree to greet me in.
This was my closest experience to being on a private jumbo jet. I didn;t see one single passenger all the way.