The songs were just disgusting and horrifying. The character designs are disgusting too, nothings appealing, etc.
It's like DiC really didn't care if they were going to stain Sonics reputation or not.
At least Sonic X followed the games SOMEWHAT.
Honestly, that's the one thing I don't like about DiC, or sometimes even when Westerners animate something from the East. They pretty much twist and change so much that it hardly ever matches the original. I mean, won't deny, I did enjoy Adventures of Sonic the Hedgehog, but that's due to the humor, and it was as close as to the games (having Chaos Emeralds and various Zones from Sonic 2, and even ending with them on a plane). The Super Mario series...I could never get into for pretty much the reasons above (script kind of sucked, nerfed Yoshi's IQ, designs weren't all that great, etc.). The Mega Man cartoon was fine and all, but...it still doesn't help the script had some pretty lame puns and what-not. =P
I'm not saying the shows themselves are bad. I did enjoy Underground a bit, and SatAM had its moments, but I'm not exactly 100% sure about the approaches they do, that's all.
Anyway, that's slightly off-topic.