I actually started trying to be a professional writer with novels, and I wrote two that exist and are around... kind of. But they never really went anyplace in particular. I still like them both. What it showed me was that you can spend years on a novel, and then it could just be, like, OK, you spent that time and that's that.
Here's a list of some of the folks who have written Swamp Thing over the years: Alan Moore, Len Wein, Scott Snyder, Brian K Vaughan, Joshua Dysart, Rick Veitch, Grant Morrison, Mark Millar. That's not even a full list, but you see my point - ol' Swampy has had some seriously brilliant people behind the keyboard in his time.
I was an enormous fan of Dan Slott's run, and John Byrne's run was a big deal for me. I found Slott's version of 'She-Hulk' first, and then I went back and looked up some of the older stuff because I liked it so much. And it was so good. It was perfect. It was my perfect comic book at the time that I found it.
'Thunderbolts' I was mostly attracted to because I really wanted to write Punisher and Elektra and Deadpool, who are characters I have always really enjoyed. But the funny thing is that over time, I came to really like Red Leader; he became one of my favorite guys in the book. Sometimes characters surprise you.
The decision to work with Marvel for a while isn't any sort of denigration of DC. I had a fantastic time there, I was treated extremely well, I have strong positive feelings about all of my editors and the DC universe of characters, and I look forward to hopefully working with them at some point down the road.