This is the first woodworking project I have done since high school (16 years ago!) and it's more ambitious than anything I attempted then!
It was easier than I thought on the whole, although I got a bit baffled by Australian standard timber sizes being totally different from USA ones. (The guy at the timber yard was all "One WHAT by two WHAT?") And because I couldn't find a 1x12 longer than 47 inches, I had to make the bench slightly shorter. I didn't anticipate how incredibly hard that would make it to calculate the cross support angles. (It's not just trigonometry, because there are multiple possible solutions).
It was the first time I've tried to upholster anything, too, so it's a bit wrinkly at the corners, but I'm happy with it.
I think the painting took the longest. I built the bench in one afternoon, but I had to do four coats of paint (and one of primer), each of which took nearly 24 hours to dry, so it took forever to finish.