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.
Bizarro Episode: Many of the guest issues in volume one ended up like this, with varying results. Especially any issue by Rich Hedden & Tom McWeeney.
Dork Age: The "guest-writer" era that came from #22 all the way through #44. Although there were some well-received stories, for the most part the majority of them are considered a huge step down in quality, often portraying the book as Lighter and Softer and overly comedic (as noted by Bizarro Episode up above) rather than the dark action-adventure tone. Eventually Eastman and Laird themselves stated that only two issues from that era (#27-28) were canon.
Moment Of Awesome: The Turtles' first battle against the Foot Clan, humiliating the Shredder by easily killing his best troops, besting him in combat, and foiling his Taking You with Me attempt.
Also, that first comic in general, for far outperforming Eastman and Laird's idea of how much it would sell, and starting one of the biggest franchises of all time.
Seinfeld Is Unfunny: The amount of violence, especially in the early issues, were pretty shocking for the time, but considering how tame they are compared to several mainstream comics nowadays, newer readers may not be able to see why they made such a big deal.
What Do You Mean, It's Not for Kids?: No thanks to the 80s cartoon, which is far more well known, this comic could be mistaken for another child-friendly comic when it's bloated with violence and gore.