You’re probably thinking about Muir Woods, well worth the short trip north.
Visit the scenic Tenderloin!
The Monterey Bay Aquarium and Exploratorium are great, though I haven’t been to the latter since they moved.
It’s a store. They haven’t made chocolate in SF for years. I’ve lived by the actual factory and it does not smell good.
I am, and should have said. Back in the distant years when I lived in the Bay Area, we just always said, “Up on Mt. Tam.” I guess that sticks with me to this day. 
Absolutely agree it is well worth the short trip north even if going to Big Sur. There are redwoods, and then there are REDWOODS. Along with the redwoods on the north coast of California/southern coast of Oregon, the ones in Muir Woods are so impressive.
Ahh, well, things do change over time, don’t they? It was fun back in the day. Thanks for fighting my own ignorance!
They might’ve kind of glossed over that to fit the mystique when you visited. It looks like they moved even earlier than I thought, 1967 or so.
Not terribly sexy and they could’ve picked a less overcast day.
When you go to wharf, you can usually hop on a small tour boat that will take you out around the Golden Gate and Alcatraz for about $20. It takes about an hour and is well worth it IMHO.
I always get the pass that gives you unlimited cable, trolley and bus rides. It’s especially handy if you’re staying downtown.
Clam chowder in a bread bowl is good.
Pier 39 is a tourist trap and the only things worth seeing there are the sea lions. Their numbers have dropped significantly over the years.
Alcatraz is a very interesting tour but it is a HIKE. Not for people with any mobility issues.
No kidding! It’s a terrific place for a foodie to go. I’d forgotten about the Ferry Building.
Next time I’m in SF, I want to visit Smuggler’s Covefor tiki drinks.
Yeah the Ferry Building market is nice. Pier 39 is the first place I’ve ever encountered (20+ years ago) where the video game token machines gave 3 for a dollar instead of the typical 4. It incensed young me.
If Smuggler’s Cove is anything like the Tonga Room, drinks are $15+.
Fun and obscure, but good for science nerds:
Oh, and since I always try to make a baseball game part of my travel plans (no idea if you’re a fan), I have to recommend Oracle Park (Formerly AT&T Park), home of the San Francisco Giants. It’s in my top five MLB stadiums. Be warned, though - the Giants are terrible this year.
But they have an awesome outlet store there. Whenever we are up that way visiting thrift stores, we drop in and my wife stocks up.
Not far from the East exit of the park are a bunch of very good used CD stores, if that is what you like.
If you end up going to the Monterey Aquarium and like antique shopping, the Cannery Row Antique Mall is just a couple blocks away. Well worth a visit if you’ve got some time to spare.
Depending on when you visit, the Point Sur Lighthouse may be open for tours. It’s closed for road repairs at the moment, but the tours up to the Lighthouse Station are *really *cool. The views from up there are some of the best on the coast. If you luck out and get to go, don’t forget a jacket!
You’ve gotten some good advice in this thread. I agree with those who say that San Francisco’s popular tourist attractions are actually legitimately cool, unlike some other cities where they tend towards the tacky. The Golden Gate Bridge and Alcatraz are truly spectacular and unique.
You didn’t specify what sort of things interest you or how long you have. I used to live in the area and luckily still get to travel there for week fairly frequently. When I do I try to take in some of the natural setting of the city because it really stands out. A common thing for me to do is to start at Land’s End (with a quick detour down to the Sutro Baths ruins and the Ocean Beach view) and then walk through the Sea Cliff neighborhood across to Baker Beach and then the trails past the batteries to the Golden Gate Bridge (and down to Fort Point, but check its opening schedule first). It can eat up half a day if you stop and explore. The scenery is just breathtaking and it gives a good feel of how the city intersects with the landscape. There is nothing else like it. If you keep going further east through Crissy Field and the marina grab a cup of coffee at the Philz truck parked there.
Exploring the Marin Headlands on the other side of the bridge is a favorite of mine. I’d either have a car for that or rent a road bike (for the hills!) if that is your sort of thing. If you do this check the schedule for the Point Bonita Lighthouse, the trail is worth it if you’re out there already.
Golden Gate Park and all its museums is another great walking tour, and I’ve always enjoyed the stairs and trails heading up Telegraph Hill to Coit Tower.
And I just found out I have another work trip there at the end of the month, and just booked my Hamilton ticket 
My advice is walking heavy because that’s kind of my thing, but the museum and attraction advice you’ve got here is pretty solid too!
I figure that as infrequently as I go to San Francisco, my wife and I can afford a couple of drinks there on a vacation at some point. I wouldn’t probably go to a joint with $15 drinks if I lived there, and I certainly wouldn’t tie one on with $15 drinks.
But 1-2 each in a once-per-decade type trip- sure, why not?
Oh, Tommy’s Mexican Restaurant on Geary is pretty good. Yucatecan style food, and good drinks too.
Oh! If you’re going to strictly be in The City, get the Muni app for your phone; they are highly discouraging cash fares. When you’ve got a connection you can buy ride tickets (regular, student, or senior as appropriate) then when the bus or trolley arrives you activate a ticket which then lasts for 90 minutes before it expires, same as the paper transfers used to be, or $5 for all day. Advantage: No connection or tapping is needed, just activate it and climb on board; be ready to show it to an inspector. Disadvantage: You lose your phone, you lose your tickets.
If you’re going to be gallivanting around the Bay Area, the Clipper card is the better bet; just about all the transportation agencies have signed on to it. You load the card with cash online or at a kiosk, and the appropriate fare is deducted when you tap it at a turnstyle or on the bus.
Good advice here.
And while you’re at it, take the subway down to the Castro stop. Just take a walk around the neighborhood. You’ll see the iconic Castro Theater, the Twin Peaks bar, lots of, uh, interesting shops. And there are walk-of-fame sidewalk plaques commemorating gay and civil rights figures throughout history.
Then, get on an F-line streetcar to head back downtown. They use authentic antique streetcars from all over the world; you never know what you’ll get. It can be a slow go up Market Street, but it’s very cool IMO.
Just be sure you get on the right “subway.” There are two of them - BART, the “heavy rail” subway, doesn’t go to the Castro; MUNI Metro, the city’s light rail system (which runs underground on Market street; it uses the same entrances as the BART stations) does.
Unfortunately, Capp’s Corner, my favorite SF Italian dive restaurant, is permanently closed.
I always take a walk to City Lights Bookstore, then up Telegraph Hill to see the WPA murals in Coit Tower, followed by a stroll down the Filbert Street Stairs.
I’m loving this thread. I’ve been feeling so nostalgic for San Francisco lately. I moved there when I got married in '99 and moved away when I got separated (to be divorced much later, but that’s a longer story) in 2002. The things that spring to mind for me are things like Golden Gate Park, catch a concert there if you can - the taquerias in the Mission and an awesome one in the Castro I used to go to all the time - the Metreon, a commerce-center featuring theaters, IMAX, a Playstation Store, the whole shebang opened up the month I moved to the city, it was like my second home - Mission Delores park - the dog park on top of Corona Heights - that English pub that I can’t remember the name of that **Zyzyva **took me to one weekend - and no end of funky restaurants in virtually any neighborhood you visited.
More than everything I’ve been thinking of the great friends I made there, most through this very board, that I’ve fallen out of touch with … which makes me sad. These were great friends, who really had my back when I needed it. I’ve been thinking of putting together a ‘those were the good ol’ days’ essay, a love-letter to the B.A.D.s, as it were. It won’t be easy, I’m much more sensitive, and my memory is much worse, that it used to be.