I haven't been soaping long enough to really have a 'hate' list, but I don't like liquid soybean oil in soap. I eat soy all the time, and have since I was quite young, as dried beans soaked and added to soups, as tofu and the whole soy gamut. No soy allergies here. But in soap, I got really bad DOS with soy. I don't cook with soy oil, though. I much prefer OO or Walnut Oil for cooking. If I make a cake, I do try to use a milder oil, but until I started soaping, the only oils I kept in the house were OO and sesame oil (I love the spicy sesame oil for certain foods) and an occasional mild oil to bake with. I did do a couple of years of cooking with CO until I got really tired of it. I went back to OO, and occasionally Walnut Oil for cooking.
When I was young and not pregnant, I did cook with lard and bacon grease, but when pregnant those turned my stomach. After becoming vegetarian all meat by-product oils left my house and not until very recently did I start to make soap with lard for my family who aren't vegetarian. But I still don't like the smell of it when I use it, so have cut back again. I've never used tallow for soap and although I can't say I 'never' will, it seems less likely that I will, and I doubt very much I'll ever be tempted to render fat myself given that I don't much like the smell of meat in any form.
I also don't like CO all that much for soap for a couple of reasons. One, it's so darned greasy! Clean-up is a real pain with CO. And two, too much of it in soap makes my skin so dry, I tend to avoid using it except in very low percentage. I don't 'hate' it, but it's just not one of my favorites.