I know the feeling well, but on this, the seventh layout I've made in 60+ years, I've learned to fight the feeling. Quyite seirous here. It might be time for you to do the same. I recently resisted an impulse to build out into my furnace/equipment room and run track around the edge of that room, etc. I recommend resistin, for two reasons: first, you can end up creating a monster - remember you have to maintain and operate this from now on, once created. Second, if you add too much at the margins of your bench, building out, you make it difficult to reach other things farther into the middle of the layout - this is easy to rationalize around in the heat of excitment when you are adding to the layout but something you will pay for every day from now on if you do it.
There is great wisdom in Texas Pete's observation - humorously made perhaps but spot on - you like building benchwork and adding track, and yes, it IS fun - I feel the same way. I resisted making further additions by reminding myself that these other things - doing scenery, adding buildings, working on vehciles and accessories, that was also fun. I found that once I got into those activities they were just as much if not more fun. You might try deferring the additions and "forcing" yourself to take up some other activity for a while, first.
and of course: if you defer this now, it will always be an option in the future, still.
