For me, it's not so much that the inspiration and motivation get stolen as much as I let it lapse. I get overinvolved in other stuff, like research and reading, and as much as I want to write to remove the words bouncing crazily in my head, I start having trouble with making myself pick up my pen. Sometimes I get stuck on a name or description, and I have trouble getting past it.
I learned a long time ago not to bother with how to books. I keep a copy of Stephen King's On Writing, and a printout of Jim's blog. I've found most of the other books are pretty useless for me because they get bogged down in all the grammar and literary terms, and they tend to repeat the same things. I don't bother with figuring out themes, symbolism, exposition, etc. I just write and leave that to worry about later. Plus I write speculative fiction, and I tend to need more category specific type things for that. Like with Orson Scott Card's book that has sections on FTL travel and world building.
If I get the mindset of "I'll never be this good" when reading books, I look at the book I'm reading, and it tends to be something like LotR, and remind myself that pretty much nobody will ever match that. And then go find a book that's pretty badly written and read it, and tell myself that if that can be published, I have a chance.