[Afton]

Goals goals goals. The implicit assumption is that your goal is to develop something specific over time. You want to get stronger, you want to get bigger, you want to increase your endurance, for example.

Since those specific goals are so common, they fade into the background. But if your goals are more or less one or more of those goals, then yes, do the same set of exercises 50-100 times (progressing weights/intensity/etc). That will stimulate improvements. Doing a bunch of different things every time is 100% better than sitting on the couch, but won't allow you to progress very much. You'll essentially only be progressing e.g. strength when you happen to overlap some motion with the right amount of increase to cause improvement.

But something that you'll do is better than a perfect thing that you'll get bored of and stop doing. Existence is the primary predicate and all that.

Incidentally, Starting Strength (the book) talks about this somewhat. He distinguishes between 'training' and 'exercising'. Training is about progressive overload. Exercise is about moving your body. If you want to change your body, you'll want to train.