A few days ago I learned that a grant proposal of mine to an agency that routinely uses panel reviews would be declined. What makes me feel even crummier is that my proposal was ranked N+1, where N is the number of grants that will be funded (N is also a very small positive integer). So, close but no cigar. The reviews were good, but obviously could have been better, and were in the usual vein of calling for tightening, focusing, distilling, purifying the idea and the message... The program manager was very encouraging about revising and resubmitting, which is what I intend to do, but still...
When I think about grant proposals, I sometimes think about a very good friend of mine, whose pastime is building custom-configuration computers; he really enjoys it and is very good at it. I asked him why he doesn't try to cash in on it or at least go into some type of consulting, because he seems lukewarm (at best) about his actual job and very passionate about his pastime. He answered along the lines of "It's only fun as long as it's a hobby. It would no longer be fun if I actually had to do it to get paid."
For an academic scientist or engineer, writing grants would be the most enjoyable thing in the world if only it weren't so darn important to actually get the money.
When you think of it, writing a proposal means you get to immerse yourself completely in research, learn a lot of new things, ask exciting and far-reaching questions, brainstorm, dream big, and distill your thoughts and ideas through writing. As an added bonus (in my opinion, at least) writing a proposal gives you an excuse to drop all menial work and cancel unwanted - ahem, unnecessary - meetings without feeling guilty (everyone is very sympathetic when you say "I have a proposal deadline"). For me, writing a grant is a guilt-free exile into what I love best -- research.
One's career and the livelihood of one's students and postdocs hinges on the success in getting grants (Professor in Training has a nice recent post on the challenges of grant writing). Funding rates are depressingly low (in my division at the agency above the funding rate is a tiny bit over 10%). This means an average faculty writes a large number of grants to get one funded; of course, I am not assuming grant awards are completely stochastic -- we all know to correlate merit with fundability --- but the number of grants that are competitive is larger by a factor of 2 or 3 than the number of funded ones; there just aren't enough funds around... Depending on your research area, some agencies do have significantly higher funding rates than the agency mentioned above that all of scientists and engineers apply to, but you have to become part of the in-crowd first.
I remember how helpless one feels on tenure track before getting that first grant. The world of funding agencies seems unpredictable and hostile, and you are wondering how long and how thin you can stretch those start-up funds...
Once you have actually received a few grants, the world of funding agencies still seems unpredictable and hostile, but there is no time to rest. Now that you have received some money, you realize that you are actually constantly running out of it and need to keep writing: there is always some grant expiring, or about to expire next year, and the student supported on it is midway through their PhD... One could say "Well, your students could always TA" but that is not a universal truth, only in departments that teach large service courses. I dread becoming one of the, admittedly very few, faculty in my department who have not had research support (and thus, any summer salary) for a number of years. They once did, but now they don't and likely never will again, because they stopped trying. I am not sure why certain people completely cease to write grants once they are tenured, but I don't think it's because they are not driven. Rather, my guess is that it has to do with disillusionment and hopelessness, as the wells of funding in certain fields dry up.
I think the only way to keep going at it -- writing many, many grants -- is to try to fully savor the pleasant, creative part of grant writing, and try to minimize the damage to your soul by the unpleasant parts (a.k.a. being declined). I believe that if a person finds absolutely no fun and no enjoyment in the grant writing process, then getting a faculty position in science or engineering may not be worthwhile.
Lastly, grant writing with colleagues can be very enjoyable, with lots of exciting brainstorms if the collaboration is a good one. An important added benefit is that you have someone to commiserate with when the grant is declined, and someone to celebrate with when it's finally funded.