I often sit on a wood barstool to work. While I have natural padding, the seat is hard! I couldn’t find a more comfortable barstool or cushion but I ordered something in that came padded with two sheets of foam. Great!
After two months of sitting on plain foam I decided to make a ‘real’ cushion to fit the stool. This is not great foam, but it was free and here. I cut both pieces to fit the top of the stool.

Once I was sure the foam fit the seat, I cut fabric for the cushion top and Easyliner Grip shelf liner for the bottom, adding 1/2˝ seam allowance on all sides.

I sewed the fabric and Easyliner right sides together using my walking foot, a long-ish stitch length, and a scant 1/2˝ seam. The grippy stuff does not slide on the bed of the machine so sew with it on top. There isn’t fabric between the Easyliner and the foam. You could add fabric, but I couldn’t see the point. Leave an opening to insert the foam.

Getting the foam in place wasn’t exactly easy, but it was possible. I pinned the opening closed and whipped it shut by hand. I would have sewn it on the machine but decided that would be way more trouble than it was worth.

I thought about making this cushion for weeks. Why? After less than an hour I have a functional, cute cushion that will last a long time. I might eventually get fancy and purchase high density foam to make another one—but not today :-).
Take a look at the projects that you keep putting off. They might be like this… faster than you think and very grin-inducing!