Archive Panic: There are a total of 1,005 episodes through the show's entire run, counting both the black-and-white 100 originals that were on EEN and the 905 that were on NET/PBS. At 30 minutes a piece, that would run 502.5 hours total, or nearly 21 days nonstop. Of course the show is very self-contained per episode and isn't meant to be watched over a long term (obviously aside from the 5 episodes that make up a week of the same topic), but still, if we want to be completely real here, there's probably no way you're going to make it through all of this.
Awesome Music: Most of the background music was improvised live during taping by jazz pianist Johnny Costa. Refusing to play "kiddie music," Costa filled his accompaniments with sophisticated runs and flourishes. His arrangements were often compared to the legendary pianist Art Tatum, which is about the biggest compliment a jazz pianist can get. In fact, Costa was given the nickname "the white Tatum"... by Art Tatum himself. Now that's awesome music.
Many episodes open with a shot of a flashing yellow traffic light that was in Mr Rogers' house before panning over to the door where he entered. A yellow light (generally) means "slow down" which is exactly what he did with the pacing of his show, especially compared to others at the time.
On some episodes, instead, we see the porch and Fred Rogers walking into the house.
On episode 1721, The traffic light is flashing on green instead of yellow as it usually does. (This is the only episode where the other traffic light besides yellow are flashing in the intro. There was no episode where the traffic was flashing on red).
Hilarious in Hindsight: David Newell, Mr. McFeely, is the head of Public Relations at the Fred Rogers Company. It works on so many levels.
There is also a genuine Spee-Dee Delivery company, though it only operates in the north-central US.
Less Disturbing in Context: The infamous picture that appears to show Mr. Rogers Flipping the Bird at the camera. While the picture itself is indeed real, the context makes it quite innocent, as it simply appears in the middle of a familiar children's finger-play that involves raising your fingers one at a time ("Where is tall-man?). Of course, some viewers speculate from his knowing grin at that moment that he knew perfectly well what the gesture would have meant out of context.
Full-body costumed characters like Bob Dog and Purple Panda were known to scare some viewers.
Some viewers also had a childhood fear of the music that played when the Episode Code Number was shown at the end of older episodes. It didn't help that the oft-feared 1971 PBSVanity Plate used to directly follow this.
Suspiciously Similar Song: Some songs used in the early days were co-written with Josie Carey, dating back to their time working together on The Children's Corner. Rogers and Carey sold the copyrights to these songs (foolishly, by Rogers' own admission), and mostly stopped using them in order to avoid paying royalties, as Rogers said that he could come up with new ones that were just as good. Indeed, some of the newer songs have very similar lyrics - for example, "I Like You As You Are" gave way to "It's You I Like".
Sweet Dreams Fuel: If you are in a bad mood, just watch any episode at all of this show and feel the blues melt right away.
Some Anvils Need to Be Dropped: While the show was never overtly preachy, author Michael Long has observed that Mr. Rogers often quietly advocated social values that were well ahead of their time, including supporting racial and gender equality in the 60s, criticizing the Cold War arms race, and advocating nonviolence during the Gulf War. As one example, the character "Mayor Maggie of Southwood," played by African American actress Maggie Stewart, debuted in 1974, 14 years before the first African American woman became mayor of a major U.S. city in real life.
Didn't contain, but was still related to examples of:
Even Evil Has Standards: 4chan is, without question, a blazing inferno of soulless evil. And insulting Mister Rogers is an instantly bannable offense. That's right — Fred Rogers is too sacred for 4chan.
Obviously, the Westboro Baptist Church did the exact same thing, albeit in the most Evil Cannot Comprehend Good way possible; they protested his funeral because he was a tolerant person and didn't speak against homosexuality. No seriously, that is verbatim what their beef with him was.
A specific example of Memetic Badass Pacifist was when he spent six minutes talking down congress from cutting PBS funding with 10 mill. dollars. It resulted with them increasing the same amount instead, as if he rolled 20 for diplomacy check.
Fred Rogers liked Eddie Murphy's parody of his own show, "Mr. Robinson's Neighborhood." To be fair, it was an Affectionate Parody, not deliberate and malicious mockery. Apparently, Eddie Murphy caught up with Mr. Rogers and told him, "You understand, we only do it because we love you."
Johnny Carson also did a parody sketch where Mr. Rogers explained where babies come from, but it was also an Affectionate Parody and unlikely any kids were up late enough to watch it.
On the other hand, in the late eighties when Burger King made an ad with a fake Mister Rogers explaining why BK burgers were better than McDonald's burgers, Fred Rogers said "You will stop that immediately!"... and they did. This was mainly because he looked too much like the real him, and did not want kids to get confused. By comparison, obviously no kid is going to confuse Murphy for Rogers, and Murphy's sketch was broadcast safely out of the way of any typical child's viewing time.
One reason why the Westboro Baptist Church is considered to be such an acceptable target by the internet is because they are willing to attack Mister Rogers—see below.
There's also the story about a pair of guys who stole his car, and when they realized who it belonged to they immediately returned it and left an apology note.
Fox News got a rather large chunk bitten out of it when one of their pieces suggested that Mister Rogers and his message was somehow a bad influence on children because he instilled concepts like self worth beyond material possessions and encouraged deeper thought and curiosity rather than blind obedience to more capitalistic pursuits. To say that people's response to this broadcast was overwhelmingly negative and critical of Fox is like saying that the sun is sort of warm.