Nothing is wrong with it, I just don't like it. I think the .308, pound for pound is a better cartridge. I feel that the .30-06 does a lot of things well, it just doesn't do everything the best. Everyone is entitled to their opinion. Nobody is wrong, nobody is right. This is a topic about "Least Favorite Cartridge", not the worst. It's all about bias and personal preference. Somebody make like or dislike a cartridge for no reason at all. Some love the .300 H&H to death, when in all reality, the .30-06 is its twin. Same with the 7mm-08 vs 7x57, or 6.5x55 vs .260. One may be slightly faster, one may shoot slightly flatter. Some people like a caliber because their dad or grandpa cut their teeth on it. I for one happen to love the .30-.30. There are a lot of calibers out there that will blow it out of the water, but I just like the cartridge. My grandpa hunted with his Winchester 94 for years. He switched to a .30-06, but once he got older, he sold it and went back to his trusty '94 because the recoil got to be too much. The first fall after he passed away, I used his '94 to take 2 deer. Every time I hold it, it makes me think of him. I guess that's why I love it so much. And no, my dislike for the .30-06 does not stem from my family.
So, let the flaming continue... I guess when I post something I should expect to get defensive since people get snappy anytime somebody may not like their favorite cartridge.