These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Americans Hate Tingle: "Mull of Kintyre" was one of McCartney's biggest solo hits, a smash all over the world, except for the U.S.A., where it was ignored. His US label, figuring that your average American would have no idea what the Mull of Kintyre was and thus wouldn't care about the song, promoted the single's B-side ("Girls' School") instead.
Cult Classic: McCartney II is this for a lot of fans. He knocked it off by himself in a month, partly as a way to test his new synthesisers, while Wings was preparing what would be its final tour, and it was released to what had become predictably negative reviews. In the early 2010s it was began to be hailed as a precursor to a lot of modern indie pop and it now sounds like one of his freshest, quirkiest and most interesting albums.
Epileptic Trees: There’s a common conspiracy theory saying he actually died in the ‘60s, an event alluded to in some of The Beatles’ works and album covers, and a doppelgänger took his place. This makes very little sense when you consider that the doppelgänger needs to do a perfect Liverpool accent and play the guitar like he did. And he was left-handed.
Harsher in Hindsight: Paul wrote a lot of songs about financial insecurity—most notably "You Never Give Me Your Money"—that started to hit a lot closer to home after his messy divorce with Heather Mills. Select lines from "If You've Got Trouble" ("I don't think it's funny when you ask for money and things") and "I've Had Enough" ("I earn my money and you take it away") seem especially prophetic.
If you consider it to be about Paul and Linda, "Treat Her Gently/Lonely Old People" from Venus and Mars is one after Linda's death.
"When I'm Sixty Four" is one as well, if you think of it as Paul addressing Linda. Linda never did get to see Paul turn sixty-four (nor Heather Mills due to their divorce), as many journalists pointed out in 2006. Heather actually broke up with him just before he turned 64, leading to a lot of Big "NO!" jokes.
Love It or Hate It: Depending on who you ask, "Wonderful Christmastime" is either a fun singalong that captures the warmth of the holiday season, or the leading cause behind December suicides.
The Storyteller: His lyrics (especially compared to other Beatles') are notable for often telling stories rather than pondering about abstract subjects. He's also a master storyteller during interviews. His age and career certainly help.
Vocal Evolution: Paul's singing voice has gotten raspier, lower and deeper over the years, particularly after the mid-1980s.
Yoko Oh No: Ironically, considering the Trope Namer, Linda McCartney is a pretty good example of this trope, especially her dubious contributions as a performer and songwriter in Wings. Her standing with the fans improved significantly following her death and Paul's failed marriage to Heather Mills.
To be fair, Paul was the one who pushed Linda into joining his band, and she always admitted she wasn't that good. She was a photographer, not a musician.