The Clippy character specifically is the part I find off-putting, but perhaps that's just an excess of relevant experience. How many times I had to explain to confused people that it's not saying anything you have to care about, or disable it for them when they're cursing at their screen because the "hide" option doesn't actually disable it you have to go into the settings for that or it keeps popping up. Which made it just another config burden when I'd be installing office on many computers in a day.
Now, a strong argument could be made that those experiences have made me unreasonable and bigoted against animated paperclips, because this is not the original Clippy. I can live with that.