Believe it or not, there's a difference. A deep thought is when you have some philisophical question you must answer. Things with meaning to your life or someone elses. Thinking deep is when you are so desperate to have a deep thought, you start making stuff up.
Deep Thought: How do I schedule time for my writing, the child care, the hubby care and the house care? Do I need more help? How do I ask for it?
Thinking Deep: If birds are so skittish...why aren't they afraid of heights?
So, as I do my morning writing warm up, I find myself pondering, is my writing deep thought or thinking deep? I mean, I make stuff up....Thinking Deep. I put a lot of effort into my writing and it's serious work that I hope to someday make a fortune and live in Tahiti off of. (Okay, so probably not, but you never know.)....I'm going to just file that under Deep Thought anyway. I imagine emotional problems for people that can actually be solved by exquisite sex...well, sex and some emotional sharing, but solved all the same...that's probably thinking deep. The emotional probs of the chars are studied, thought out and coherent to the plot...deep thinking.
Man, where is Jack Handy when you need him?
Perhaps writing category romance requires an even balance of the two. Who knows, non-fiction is probably a solid block of one or the other. I guess the important thing is that we think at all.
But why aren't birds afraid of heights?