My other job was as a VAX sysadmin for a market research firm in Chicago. My boss there, Hank, was a witty guy and he gave me all sorts of startup advice that I still think back on to this day. I asked him how he became the owner of a little survey firm in Chicago and he said "bad career move." Heh.
One thing he said really stuck with me. He said that, even if I wanted to start my own company, I should first go work in a really big place, to learn how they do things. They'll teach you all the industry knowledge that you'll need later. He also said if I didn't work in a big place, I would never be able to comprehend how completely messed up on the inside they can be. And that knowledge would be useful if I was a little company trying to compete with big fish later on.
I didn't work for big fish for a just a little while, I spent about 15 years there. Commodore, AT&T's Unix System Labs, Sun Microsystems, and the whole Netscape-AOL-Time/Warner slow motion train wreck. Sun had 30k employees when I was there. Netscape was 2500 heads in 1998 but after the AOLTW merger there were over 200k employees company-wide. I think of my 4 years at AOL as my MBA. I did stuff outside of work too, I ran a commercial game on the side, released a lot of open source software, I had a T1 into my house in New Jersey and was running a little ISP hosting thing. But the corporate education was uniquely valuable.
For one thing you're exposed to the breadth of industry best, and worst, practices. You don't have time in a startup to stop and take an internal 2-day Managing Within the Law class. That kind of training is routine for new managers at big places though. What does ISO 9001 accreditation involve, what kinds of terms are standard in an SLA, how do you deal with vendors, how are deals done, why is the QA manager always so pissed off. Good things to know. :-) Plus the opportunity to work with a large number of people and form contacts that can be useful later.
You need to spend time in the belly of one of these whales to develop an understanding of how big companies "think". Beyond little cliches of wisdom, it's a more general kind of knowledge that lets you empathize with and predict the way big companies behave. Groups of people have emergent behavior separate from any of the individuals. You have to be able to understand the drives and patterns of how this emergent group "thinks" to understand its actions.
VCs need to be especially vigilant, if they haven't logged time inside a product org. They get a vast store of knowledge and wisdom from having a great vantage point to see so many deals and follow so many business, from start to whatever end they come to. But if you haven't spent time trying to turn gears in the belly of the beast, it can be like trying to coach without ever having played the game.
Sometimes we see job candidates come in, bizdev, sales, programmers, across the board, who have never worked in a really big place, and you can tell. Of course if they're good we want to pitch them to work here and figure we can train them and they'll learn, but a lot of times what they really need to do is go soak in a big place for a while to develop their game.
So if you're starting your career, make sure you spend some time in a top quality bigco. Pick one where your profession is front and center. If you're a programmer don't do it at a company that isn't about software tech. That means don't be in the back office at a trading firm in NY. Other guys are the stars there. Get yourself to the mecca of your industry, wherever that is, and get hired by a biggie. Don't be a consultant. You don't learn to live inside an org on an hourly clock. You need skin in the game. (If you're still in college, don't wait tables or deliver pizzas. Get a job related to your career.) Soak it up and then you can move up, or move on. :-)