I think it is always a process. I think the question is whether the process is a straight line or a long and winding road! 
As I mentioned to you, my first years in forex trading were in a commercial bank forex dept. If one was having a bad day you didn’t just go home! Actually, the vast bulk of work there was not speculative trading at all. It was mainly customer driven: customer orders and covering the bank’s own related exposures. One had a personal limit to take speculative positions, but there was always a lot of other routine work that had to be dealt with. The day always started with a group meeting discussing markets, orders, exposures, etc. So one’s speculative trading was always only a small spot on the big picture. One doesn’t get emotional about that, especially when it is the bank’s money anyway!
But once I changed employers and started as a retail trader, it was a very different environment. It did actually take several years to fully adapt to small scale positioning and exposures and targets and stops - and risking one’s own money.
But I think the key is still to have a “big picture”, a structured and detailed plan about how one is going to trade, what strategy, what instruments, what risk exposures, etc. Then one is no longer blinkered and “obsessed” with just the current trade. It is only a one step in the plan. And it is the plan that is monitored and adjusted as necessary, or desired, as time unfolds. In this way, the process evolves in a continuous, systematic, and progressive manner.
It is often said that a good trader can profit even with a poor strategy, but a poor trader will never succeed even with the best strategy. And I think the message lies clearly in that statement.
As you say, different people will obtain different results even with the same strategy (unless it is automated). And the clear reason for this is that the result is down to the trader and not the strategy at all. And yet we spend nearly all our time focusing on strategies instead of on the real issue - the trader himself!
You are absolutely correct that no one would trade my strategy the way I do because it is so discretionary and a lot of the decision input comes from outside the chart itself. I only have a few MA’s on my charts, nothing more. It is enough. But I do look a lot at other external factors as an overlay on top of what the charts are suggesting. This is surely what “discretionary” means?
One of the key attributes of the trader himself is knowing when not to trade. The market does not kindly offer up a trade every day and we shouldn’t force a trade onto it. Then there are upcoming data releases, public holidays, global events, even weekends, when we need to think carefully about what we are doing.
But these are topics that have been discussed many times everywhere. I am just trying to emphasise that the strategy itself is not the answer to success, it is you, the trader. All strategies are built from the left hand side of current price - but we are concerned with what happens on the right hand side of that price. The skill in reading the likelihoods and probabilities on that side is where the money lies - and only then if adequate risk/management criteria are observed.
Just some thoughts, all of which are entirely personal and not intended to influence anyone else. Everyone has their own views on these issues - but they are worth talking about anyway! 
