I just spent a week in Northern California with the wife and some friends, visiting San Francisco, Yosemite National Park, and Sonoma wine country.  Here are my thoughts: 
  • California is big and the landscape is varied.  We went from the ocean to mountains to farms to rolling golden hills all within a couple hours.
  • Traveling with another couple wasn't bad.  We didn't hate each other by the end of the trip.  Any more than four people, however, would have probably made everything much more difficult -- seating at restaurants, rental cars, simple decisions.
  • San Francisco is a cold, gray town.  There is literally a cloud hanging over it at all times (that I've experienced).  You can see it as you approach from any of the neighboring cities -- crystal clear skies, 85 degrees; then overcast and dull, 60 degrees.  When the first people settled there, why didn't they choose Oakland or San Jose instead?
  • It was probably just a coincidence, but pretty much everything I tried to do ended in failure.  We stayed near the financial district on a weekend, which meant almost all restaurants were closed, and nothing opened at a reasonable hour.  Trying to get breakfast before 9am was a serious issue for some reason.
  • Yosemite was breathtaking.  But it's not doable in a day when that day includes a drive from San Francisco.  Getting to the entrance of the park is about 4 hours; getting to the actual stuff in the park is 6 hours.  But wow that place is big.  Big rocks, big trees.  Pretty amazing.
  • Sonoma was fun.  We happened to arrive the day of a city-wide party, where everyone was drunk on wine and dancing in the town square.  The wineries were beautiful and fun, but the tasting fees  were a little ridiculous at times.
  • I don't understand why California wine is so expensive.  If they grow the grapes, make the wine, bottle it, and sell it to customers all in one location, how is it $30 a bottle?  I can get a bottle from halfway around the world for $10, and I can't tell the difference in quality or enjoyability.
All in all, it was a fun trip.  But I doubt I'll go back to San Francisco.  We overheard a tourist say San Francisco was the best city he visited.  Clearly he's never been anywhere else on planet earth.