I loved my maternity leave - but then I really hadn't liked my job.
I remember at the halfway point, I got really depressed as it felt like the countdown was on until I had to go back, even though I still had another six months off!
As it happened, when I returned to work part time I was moved to a much more enjoyable position.
I'm about to go on ML again and I feel very differently - I'm really going to miss my job and I can't believe I'm going to be at home ALL the time again.
That said, I did find the first time around that the realisation I now had limited time to myself forced me to make the most of that time. I love writing, and I did a hell of a lot of it whilst DD was asleep. It definitely made me feel better, and kept my brain active (which is essential for sanity and wellbeing).
It was hard to find time to read, so I invested in a few audio books. Meant I could multi-task. Plus like others I went for at least an hour's walk in the day with DD, and if I didn't manage it, I'd go alone after DH got home.
This time it will be harder, but I have the benefits of both experience and a can-do attitude, so I'll fit the writing in if it kills me!