i don't give the roof of my mouth a really thorough brushing, just a once-over. I have a habit of sleeping with my mouth wide open and then when i wake up my whole mouth feels grotty and in need of a good clean!
I always brush mine, and have done for years without giving it much thought. That is until the other day when my 6 year old asked me what I was doing - suddenly I was all self-conscious! Odd, don't you think?!! Anyway, he's started to do it now too, and it cracks me up because it obviously tickles him but he perseveres no matter how much he squirms. It's very entertaining!!
I think it's a good habit to get into, and you're not alone mistys!!