Influences - How to Use Them, How to Avoid Them

I'm very fortunate to have a writing group at work.  We meet every Monday during the lunch hour and, well, write.  There's also a fair amount of discussion, as we try to figure out the best ways to put something together, work through issues we're having, or just complain about how things are going or what our characters are doing.

Today, one of the member mentioned that the book she's working on has morphed a bit from the original plan, due to the fact that her mother had been writing a novel and sending her chapters to read.  She'd noticed that, after reading the chapters of people dying of starvation, she had started writing about issues with hunger in her novel, which had previously not had any such issues.  It made me think of just how much we can be influenced by what we read, watch or hear, and if we should try to limit that kind of influence.

I freely admit to being the type of person who is emotionally battered by books.  Every time I've read Mira Grant's Newsflesh series, I find myself crying while reading or thinking about it, and anxious for days afterward I finish.  Movies and television can have the same effect on me, but not often, and if it does affect my mood, it's more likely to be due to shaky-cam cinematography than due to the story itself.

Regardless of how some writing can affect me, I don't tend to find the specific ideas influencing my writing - I'm not likely to start writing about zombies after finishing the Mira Grant books, for instance.  However, I will find that the style of the books I've read will influence my writing.  If I've recently read a lot of Terry Pratchett, for example, I'll find myself making asides and trying (and failing) to imitate his type of witty humor.  I can usually keep myself from using the obvious parts of things I've read or seen, such as characters or plot, but the subtler style imitation is harder to avoid.  In general, though, letting something sit for a little while and coming back to it later helps clean up some of the questionable stylistic choices I'd made.

I'm not saying that all influence is bad.  Every author, artist, or other creative person has been influenced by the combination of life experiences and media consumption of their entire lives.  The best ones are able to be influenced without looking as though they've "stolen" something whole cloth, and they're able to make it into something new and unique.

Your turn.  What kind of influences have you noticed?  Do you purposefully try to keep them out of your writing, or do you try to incorporate them and make them into something different?