That's pretty much what I thought: fussing needs to be left to settle. I find it hard to distinguish between fussing and crying, though, as does my wife. Last night, for example, our daughter woke up wet and fussed with some escalation, so I went in and changed her, but after settling somewhat after I'd put her back down and left the room, she kept fussing for a long time, and very loudly. I don't think it ever turned into a real cry, but she would shout in a really high pitch and quite loudly. It really sounded forced to me, though, like she was trying to make herself cry, but not quite succeeding. Does that happen, or was she really crying and I just thought it was a mantra shriek? A couple minutes before she finally settled herself and fell sleep, though, my wife turned over on her side and asked, "How is this different from crying it out?" and I didn't know what to say except that it didn't sound like a genuine cry to me. It really did sound forced.
Am I misinterpreting it, and actually just letting her cry it out? Should I have gone to the door last night and sung to her until she went to sleep? Did I betray her trust?