I don't think your question is dumb at all because I have wondered that very thing several times. The only time I want my thread to match is if I am topstitching something...which is very rarely on a quilt. I use an ecru or gray almost all the time now....I buy the biggest spool I can find.

I use a neutral color for my piecing. Otherwise I would be changing threads all of the time, instead of piecing!

Same here.

A question for those who match their thread, If you sew pink and red together what is the color of the mating thread.

I use off white thread on a cone for everything.It shows,but I don't care & I'm the boss.

I do mostly scrapquilts, so I use all my bobbins of every color. It doesn't matter to me as the sewing threads never show. If I was machine quilting, I would use matching thread and bobbin. In machine embroidery, I try to match my top and bottom threads, as no matter how I set the tension, the bottom thread somehow appears on the top at times. Since I don'tlike to mess with tension, I use the same top and bottom.

the only time people are really stressing over their thread colors matching is when doing applique, or quilting ...the stitches show and (at least with applique) you want them as invisible as possible so a good match is needed. for quilting it is easier to see the design over the (thread) if it blends in.
for piecing i just use what ever neutral color is handy...unless working with black or very dark fabrics then i use dark thread.

For piecing I usually use a light to medium gray or a light cream if its stitching on white or very light fabric. I also use Bottom Line for bobbin thread.
for applique I usually try to match the fabric as close as possible or if I want to accent with stitching on top (zig zag or satin stitch) I use whatever will contrast well. For quilting it varies, sometimes I want the quilting to be featured and sometimes not, so choose thread that will do that job.

I don't either - on;y for applique

I don't match threads - I tried to use neutals whenever possible