OK fine! Maybe it doesn't have the biggest collection of continuity errors out there but it sure does have a lot of them. Obviously only the die hard fans will even notice some of these errors but there are others that, in my opinion, show great inattention on the part of the writers. Let's start with the "not so serious" little slips.
When the outside of Cory's house is shown from the front, we see a window on the left side. However when we see the same house from the inside, we see a hat rack where the window should be.
When the guys were in the seventh grade and they would walk on the hallway, the same room was used in different occasions to be the boy's bathroom, Mr. Feeny's office and a guidance counselor's office.
In the year when Cory starts attending high school, the locker right next to Mr. Turner's classroom had many different owners all season long. It belonged to Frankie, to Cory, to Shawn and to Eric.
Now let's move on to the bigger mistakes in this show.
The way Topanga and Cory met, how long they had been together for, and how old they were when they met changed multiple times across the series.
On the Pilot episode, it was supposed to be 1993 and the guys were all eleven years old and were in the sixth grade, which means that they were supposed to graduate high school in the year 2000. Instead, they skipped two whole years of school somehow, and graduated in 1998.
Also Topanga's mother's name used to be Chloe during the show's first couple of years, but in later episodes, her name was magically Rhiannon.
But the biggest mistake in my opinion is definitely this one; both Shawn and Topanga had siblings in season one, but later on were referenced to as only children. In season one, Shawn mentions his sister Stacey and on another episode Cory video tapes Shawn's older brother stealing a computer. However in the last season when Jack is introduced as Shawn's half brother, Shawn says he always wondered what it was like to have a brother since he was an only child.
Go figure!