I don't know if I'd say I weathered it or if it weathered me, but I went from roughly $324,234.69 invested assets Feb 29, 2000 down to $142,434.73 Aug 31, 2001 (56% drop). Took me until October 2004 to reach even, and I was only basically back to even with the amount I'd contributed at that point. That was a painful lesson about being overly concentrated in individual tech stocks (especially Cisco Systems, ugh).
Hit $1,014,399 May 2008 and fell to $755,162 by March 2009 (26% drop), the limited drop was mainly due to sheltering some of my gains. I knew I was ahead of the game again and didn't want to blow it! Sucked to lose even more money this time around, but recovered my losses by June 2009 (which is shocking to look at in retrospect, the bounce off the bottom was huge! If you blinked, you missed it, and many people thought they'd wait for a pull-back to jump in...).
Things have been better than I could've dreamed of since those dark days and I find myself singing
Life's Been Good from time to time, although I'm too Mustachian to spend like Joe Walsh.
Don't know what advice I'd give to people other than what I see already out there - 100% index funds initially on your way to the number and then shelter some when you see fit, which is obviously the hard part. Paraphrased from Bogleheads, 'continuously assess your willingness, need, and ability to take risk to set a target asset allocation and re-balance (or adjust contribution allocation) periodically.' That's about as simple and complicated as the accumulation phase seems to be. Having experience losing a lot of money on paper (imagine a 50% drop) really helps assess your ongoing 'willingness, need, and ability' to hold equities.
Of course, you can mess around with 5 - 10% of your portfolio if that floats your boat or try to load up on dividend stocks. Maybe add real estate... but, most of these things tend to underperform and/or encourage active investing. Index funds are the right mix of 'boring enough not to follow too closely' and 'exciting enough to squeeze the finances and buy as much of as you can'.