Someone told me and subsequently I tell other people, the two most important things for a writer to have in this industry: Patience and Persistence.
But the truth is...
Waiting is torment. Yet people require it of you at every stage of the road to publication.
When you're looking for an agent: if the process is at it's quickest, you wait for agents to read the query, your ms gets requests, and you wait for the agent to read and respond.
Once you have an agent: you go out on submission and wait for editors to respond.
Once you have an editor and a book deal: you wait for your contract, you wait for your editorial notes, you wait for your copy edits, you wait for your cover, you wait to see your manuscript actually become a book.
The thing is, for all the waiting writers do, industry professionals are also waiting right along side them.
Many of the offers of representation I've made, I've waited to find out whether or not that writer would choose me (all the while, going "pick me, pick me!" and annoying everyone in my office with my constant "But I'll die if I don't get it" whining). When I go out on submission with a manuscript, I'm waiting for editors to read (cue more annoying whining everyone in the office has to deal with - I'm horribly impatient).
Editors also have to wait. During auctions, they're waiting to hear if they're going to be able to get the book they love so much. When buying a book, they often have to wait for approval from bosses, from sales and marketing. Then they wait for the art department for the cover and the booksellers for the order numbers and then the reviewers, bloggers, and book buying public to hear how the book does.
So, how do we cope with all this waiting?
I read more and throw myself into long hours at work (and whine to my colleagues). Which works for me.