My first instructor "ghosted" on the controls, a lot in fact. Looking back, I don't think he was even aware of it. But at the time it caused me all sorts of problems. I seemed to be learning incredibly fast, and not finding anything that difficult. I didn't realise there were any problems till I had a check with the CFI prior to being sent for first solo...and I couldn't do takeoffs and landings!!!
Well, everyone sort of glossed over it, and said we'd carry on with the syllabus and do a bit of takeoff and landing practice at the end of every lesson, and I carried on with the same instructor. But now I was suspicious, and I'd worked out myself what must have been happening. And being more aware, I'd feel it too. I'd say to him, "But you were helping me, weren't you", but he'd swear he wasn't. One time we were hovering to land, and I just stopped lowering the collective, to test him...and lo and behold the helicopter landed itself!
By this time I was confused and upset; I thought he was deliberately tricking me and I didnh't know why. I didn't want to fly with him any more really. But I was too determined to go solo ASAP to want to rock the boat by asking to change instructor.
But the day after my first solo, with the confidence gained from that, I became really, really angry. I thought he'd been doing it deliberately, wasting my time and money. I phoned the school and said I could never trust him again, and either they found me another instructor or I was changing to another school! They did, and things were OK from then on. But it took a long time for that anger to go away. In fact, I stopped enjoying flying for a while, and felt disinclined to trust anyone.
Now, you can say I over-reacted - and of course I did. But nevertheless, that's the sort of thing that can happen. And the overconfidence I acquired through thinking in my first 20 hours that I was a natural helicopter pilot actually caused me all sorts of problems for a long while. I can't blame all that on my first instructor, and I don't; I didn't have to react the way I did. But it's worth bearing in mind that what you do as an instrutor, even early on, can have long term repercussions for the student, long after you're gone.
As a new instructor, I was quite determined not to make that particular mistake. As a result I probably gave my first students a little too much control, bearing in mind how new I was. I like to think I'm now approaching the right sort of balance, though it's hard to know of course.
Still, at least I learned something from my first instructor's mistakes!