Well, I watched the old 80s ponies as a small child, and I watched it like I would any other cartoon.
As for gen 4, I started hearing about during its first season, and I was like, "Lauren Faust made this? Well, Powerpuff Girls is the best thing ever, so let's give it a shot". It turned out to be the best flash animation I'd ever seen, and overall a better cartoon than anything else on at that point. The 00s was a desolate wasteland of animation, so I watched on with curiosity and fascination.
...Although the first time I searched for 'new mlp', I accidentally found some sleepover episode from season 3 or whatever, and I couldn't believe people actually liked that stuff. It was a few days later that I found some pictures of the show and went on a new search.