haha man u described me perfectly. i struggle to sit and tattoo ...it begins to drive me nuts after 35-45 minutes and i usually break after an hour and gotta take a smoke break or something. crazy thing is i only need 3 -4 minutes to talk away from the tattoo and i can sit down after that refreshed and focused . but after 45 more minutes i feel like i cant sit still any longer .
u can see this effect in alot of the old masters oil paintings.
paintings look great man! id try to add some sfumato to your work (smoke like edges). makes a huge difference with realistic painting...but tricky to pull off. also there is a realism oil painter by the name of scott waddell. he has some short videos on youtube which are amazing. definatly watch them . his video on color and chroma are so informative. made a big difference in my oil painting and my color tattooing.