That is exactly what I would do. If its an interval workout and I couldn't make my power targets, I would 100% abandon the work-out, just cool down and then stop. The exception to this would be a work out in which the power target of a particular interval is not 100% vital- for example, I might be instructed to do a set of intervals with alternating high/low targets but be told in advance that its holding the lower power target that's important, its ok to decrease the high target by X percent if necessary.

I also just last week aborted a road ride early, I was planning on a 3-4 hour ride, started out feeling a little tired, didn't feel any better after 90 min, so I called it a day and went home, only got a 2 hour ride in. My instructions for Fri/Sat were 10 hours total of tempo riding on the road. I did 2 on Friday and 5 on Sat. Coach has not gotten my data, but I had a great ride on Sat and I'm sure he's going to be happy with it.

The point is riding when fatigued is counter-productive, it only does harm. I guess maybe the question becomes how do you distinguish what you feel during a tough workout from the counterproductive "I shouldn't ride" fatigue? Easy on the trainer- you can't hit the targets, just stop. The road is a little more of a judgment call. I probably *could* have managed a 3-4 hour tempo ride last Fri but I could tell the way I was feeling that I wouldn't be able to follow that up with a 5-6 hour tempo ride the following day, that's maybe just a little bit of an experience thing. The Sat ride was on the course for an event I'm preparing for, so it was more important to me to be relatively fresh for that. It also helps that I kind of have an idea from the workouts coach has scheduled for the week what he's expecting as far as a weekly training stress goes, and I kind of know now what I'm going to produce on some of these rides. So I know I can cut Friday short, ride better on Saturday and it will probably work out as he intended.

Haha and for me 'nothing' is certainly not inevitably followed by 'more nothing'. I did not hire a coach to motivate me, I'm completely self-motivated. If anything, the coach is there to keep me from doing too much. I am way more prone to counter-productive over-work than I am to doing too little.

I will say that one positive thing about having this coach is that when I was trying to follow a canned training plan from a book, I was constantly wondering if each workout was appropriate for me. "Is this workout too hard for me?" Then if I was struggling with it, I would wonder if I should modify. Likewise, if a workout went well, I'd always be wondering after if it was too easy. At first with this coach, he would send me these workouts and I would think 'this is a pipedream, no way can I do that for 2 hours'. And then lo and behold, I could. Now I don't have to think about it, he just tells me what to do and I do it. Then you pay attention to what's going on and you start to get the gist of it. It really a huge luxury compared to a canned plan, just not having to worry about overall arc of the plan.