It gets personal and really depressing. In my mind I can visualize these projects finished. I'm riding the thing in my head. When it dies, so do those visuals. It's hard. Especially when you have to break it to the team you just killed to build a presentation that went sour. They trust you to sell it and make it real. I had to recast a team for Indy at DL and that was hard as the Ride was still a "go" but management did not want the concept the team had done. I was brought in to start over with a new group. Tough audience. They actually had a day for that team to discuss and "mourn" the loss of the concept! It was actually called that. So the depression is team wide.
DLP MSUSA was the 1920's theme and we spent a year designing it, till I returned from vacation and it was killed. That was tough to take. Eisner reconsidered two years later and said he was wrong and we should have done it! (I wanted to shoot myself as we were still working on the 1890s version and had not opened yet!)
Some projects should not get built and guess what, maybe the boss is right and your ride isn't worth doing. You have to be humble enough to recognize that every idea isn't destined to be built. But...sometimes another project competes for the same $$ or location and a rival "poisons the well" with a rumor or an outright allegation that your project will actually cost double, or can't be done, is bad show, etc. just to kill it and create doubt. That creates more drama and if you lose because of that, deep divisions and suspicion. I had that happen on my first project, where a senior person came in and threw out a huge number before my work was even estimated. They said it was a waste of time to estimate and so it was killed without ever having a chance. I was wary of that guy ever since. Losing without reason is more depressing that just losing. I try to let go of the product and not be so attached, but in the end, it's why what you do is good because it IS personal.
I used to kid people in my bad Austrian accent, that I was unkillable like the "Terminator". If you hate one idea "I'll be back" with another and another..and so like getting a new puppy when "Old Blue" dies, you just have to move on, it's the best remedy, and save those ideas for another day.
Thanks for giving me the chance to vent!!! I feel much better now.