I suppose the pronoun 'it' appearing in almost all these sentences, with some exceptions, is impersonal, and is used to indicate the situation described by the following clause.
I really appreciate it when you ... ─ source
- I appreciate it when you have time for me, so I don't feel rushed.
- I appreciate it when you acknowledge the time and effort it took for me to get here.
- I appreciate it when you help me understand.
- I appreciate it when you provide important information in writing.
- I appreciate it when you acknowledge and respect what I know about my child.
- I appreciate it when you acknowledge and respect what I have learned from others - even the Internet!
- I appreciate it when you give me unbiased information, and let me make an informed decision.
- cf. It's very helpful when you clarify your role in the "big picture."
I don't appreciate it when you're being mean to me. ─ source
The Longer you wait for something, the more you appreciate it when you get it. ─ source
I really appreciate it when people at least try to be understanding. ─ source
I appreciate it when rooms have hardwood floors and not carpet. ─ source
I appreciate it when I smile at another girl and she smiles back because it's like wow not all girls are spawns of satan. ─ source
You have to experience the wrong kind of love, in order to appreciate it when it's right. ─ source
We really appreciate it when dancers come over to our place on the spur of the moment. ─ source
I so much appreciate when anybody tries to make something and tries to be an artist - I'm happy to see the work. ─ source
Do waiters/waitresses appreciate it when patrons stack plates? Why or why not? ─ source
Players appreciate it when the game is well made. ─ source
And a sample sentence with some part of the paragraph in the current job, Swimming w sharks:
... ... We had talked about why many people seem to have so little interest in issues that directly affect their interests. It is indifference and apathy, or have many subjects simply become too complicated for outsiders to understand? To find out, I had launched an experiment for a Dutch newspaper. I had taken an important, complicated and apparently boring issue that I know nothing about─sustainable transport─and asked a beginner's question: are electric cars a good idea? I had put this to an insider, whose answers led to new questions, which prompted interviews with other insiders and so on until a sort of 'learning curve' of articles and stories had come about. Insiders were happy to make time while readers seemed to appreciate it when you started from zero.