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.