Sanding. Every time I think I'm finally done sanding, I'm not. LOL
Oh yes this! And often it looks fine until you paint over it and realise you were not done sanding after all.
I try to avoid sanding as much as possible, meaning I'll try to smooth out everything as much as possible before the clay is cured / has been baked. And when working with cured clay, my preferred method is carving.
Bait prepping is also one of my least favourite things. I've been lucky to buy a lot of baits that have come already prepped, such a luxury!
Rehairing is not my favourite part, no matter what method I use. It's actually fine once I get going but it's something I really tend to procrastinate on, it's difficult to get motivated! It's also why alt rehairs aren't really my thing although I admire the work of others.
Plus some of the ponies in my own herd have been waiting for new hair for *years*. Rehairing customs is enough for me, haha.
Cleaning up - I try to be more careful about responsible handling of waste. Years back when I didn't know better I just tossed bits of dried acrylic paint into the bin, before I learned that even non-toxic craft paints aren't something you can just dispose of with normal household waste (where I live it gets burned for energy). Nowadays I collect dried paint into a jar and try to be careful when cleaning my brushes, making sure I get almost all the paint off the brushes before rinsing them. I mean, all of this is important but I'm a person who's overly anxious about stuff like this and I don't like the stress it causes me... and I absolutely hate cleaning my palette.
Which is why I do it maybe once a year, haha.
Trying to avoid cat hair and dust particles! I'm pretty confident with my painting and sealing work, but those pesky particles...! Well, it's an old joke that cat hair is the secret ingredient in our kitchen, and likewise I suppose you just can't get a Griffin custom without some small particles trapped under the paint or sealant.
And of course it's always annoying when
things don't go the way I planned or I end up making a mistake that's difficult to fix... But I've also had a lot of happy accidents, and sometimes things turn out better the second time or when I need to get creative to fix a mistake, so it's not all bad.