The nostaglia goggles are strong in here.
I grew up in the 90s, but I hated almost every show. The only reason I watched shows like Catdog and Hey Arnold was because I lived in an apartment and there was nothing else for me to do. The only shows I actually liked as a kid were The Powerpuff Girls, some show about a talking blue dog (I can't remember the name of it for the life of me), and Invader Zim. As an adult, I occasionally like to watch Courage the Cowardly Dog and Spongebob (I watched Courage when I was younger, but the show didn't scare me when I was a kid and as an adult, I have more of an appreciation for nightmare fuel). I never was a fan of the shows on Disney, but that's because I hated anything that wasn't a cartoon and I outright gave up when there was some sitcom on 90% of the time I turned to that channel.
As an adult, Cartoonnetwork has one redeeming show and that's Adventure Time. Other shows like Regular Show and Gumball just aren't my thing and I really hate Cartoonnetwork's push to make live action shows a thing (Like The Incredible Crew or whatever that piece of crap was called). When Cartoonnetwork brought on Steven Universe, I really really tried to like it, but I just can't. And Uncle Grandpa is a hit or miss for me.
As for Nickelodeon, I have very mixed feelings about it. iCarly was a great show that suffered one major problem that made the show unwatchable - Carly. If their main character hadn't been such a Mary Sue, it would've been a great show imo. At least in its earlier days. Once the show started forcing situations where Miranda Cosgrove would start singing (so that Nickelodeon could make an iCarly CD and profit even more), the show's only redeeming features (Sam and Spencer) couldn't save it. Then you move to Victorious, where you have a great cast full of interesting characters and this awesome setting (a school specialized for the arts)...and then there's Tori. You have Cat and Jade, who have way better singing voices than Tori, but Tori is always the one picked to perform in huge concerts and be in movies and whatnot. Both iCarly and Victorious had so much potential until the title characters ruined the shows.
So basically...I like the current shows on Nickelodeon/Cartoonnetwork more than I did when I was growing up. All of Nickelodeon's sitcoms are plagued by awful Mary Sues and Cartoonnetwork's only good show (imo) is Adventure Time, but considering that I disliked Doug, Hey Arnold, Catdog, Dexter's Lab, etc., I'm actually getting more enjoyment out of their current crap shows than their older crap shows.