Although if you are playing chess, obsessiveness with the game would probably be good. But of course it will vary greatly from person to person.

Actually, the sort of obsessiveness it produces diminishes the ability to switch attention, so people get obsessed over a particular train of thought and are unable to evaluate other strategies. Basically you end up obsessed over that one strategy, and motivated to do it, instead of taking a step back to re-assess.

When I first started taking stimulants for ADHD and was trying to get the right dose I was confused because nothing was happening at first but finally reached a tipping point where it was working, but it was like a more intense version of my normal hyper-focus I would get at 8pm after "warming up" for 12 hours, after a couple of days it settled in between where I get the easy ability to switch attention without getting annoyed, or not realizing.