this is EXACTLY what I was going through with another INFP (relationship wise). Especially #2 and #3. Really frustrating.
Hhmp.. You know, it is nothing personal, but when I read this and basically position myself in the shoes of that INFP, I am getting a little annoyed. I guess this is because the difficulties in motivation really are a lot of trouble for me, and when people even imply it, I get a little touchy. So, the bullshit part here is that I would like to shout "Shut up, I already know I am bad at that and have looked at it from all the angles I can imagine, but just can't find the answer. You can't do it for me." Of course I rarely do this, since I try to be a civilized person, but still, that might be my bullshit and I am on my knees in front of it.