I'm still young in quilting experience, so I have many things to learn or try. In the earliest years, I said "I'll never--" to several things I'd see, because they looked too challenging. But I have done them. So I try' not to say "never" but 'probably won't" because I know myself. Mainly I don't like 1) tiny pieces (under 2" square) so probably won't make anything too large that requires them 2) certain blocks (one that looks like a swastika--would never--yes, I'll say never-never use one if I got it in a swap 3) intricate paper piecing (I like bigger blocks and lose my interest in something that takes a lot of concentration for a long time .
I might never make a 2-color quilt because, as hard as I try, I can't seem to limit myself to only two. It would have to be a 2-color challenge, but even then I would not use the same two fabrics. To me, I know I'd fizzle out if I had to do umpteen identical blocks in only two fabrics.