Satisfied

I spent the whole day working on my most recent project.  We have an extra room in the basement, under the garage, which really has not been usef for anything since we've lived here.  So i planned a Sauna, walkin shower, toiliet, workout and relaxation area.  The room is quite large, but with all of these separate areas i had to plan very efficiently.  It's one of those projects where i have a vision exactly in my head of how it should look.
Well today i finally started working on getting a connection for hot water in the basement.  All day i've been hammering, drilling, cutting, etc.  Running between the basement and the ground floor. 
But, i made it! there is now hot water in the basement, and i'm one step closer to realizing this project.
Now i'm sitting here with a glass of wine and feel pretty satisfied, and i began to wonder why this level of satisfaction only occurs after an accomplishment like today?  I'm thinking about why i only feel this way when i've actually done something that can be seen or measured or touched?  Other people can reach satisfaction with complete chaos surrounding them, but not me.
Strange, but it's a nice feeling....for a while