I grew up with the Pokémon video games and TV show as well. I watched a lot of episodes, but after a while, I grew bored of it. The thing is, the TV series grew very monotonous and repetitive, always having Ash defeat Team Rocket just like he has several times before in every other episode.
I also noticed that as the series progressed, it tried to get more kid-friendly. I didn't really mind that, but it seems hypocritical when characters always go on about how fighting is wrong when they usually solve all their problems by fighting.
Another disappointment I had was how it did not have any likable characters. Most of them were just stock personalities, be it the rash protagonist or the spunky sidekick.
Now my opinion only is based off of the English dub, so I may be missing out on whatever Japanese viewers got, but I don't think there might be much of a difference between the two. I still like Pokémon, and I am a die-hard fan of the games, but the TV show didn't really get me that excited.
Besides, everyone knows the manga is much better.