It's funny but there is (and has to be) a threshold where someone feels good, or starts to feel good.
20 years ago I routinely gassed over a gram of Organons finest on the unemployment government rebate and felt even better though How times change..
When I first stumbled onto this forum years ago I thought I was in the twilight zone, with people using insulin syringes and splitting hairs over doses that seemed, no offense, absurd. I gave it a go though and ended up even nuttier than some of the guys I previously thought had it wrong - going down to 70mg Prop per week to see how I felt.
I can't speak for others, but minute changes in dose do have a significant effect on my mood and libido, but only when playing with super low doses. How much of this is due to actual blood levels of test vs feedback loops on other things I can't be sure of..
To answer the OP, I use 20mg test prop daily and it puts me just over the top of the range for TT and high normal for FT