I certainly agree with this quote but for me, sometimes I find those mentally challenging things frustrating even though they are VERY good for you. That said, I'm always amazed at the things I learn - even in my old age
The reason I chose this quote is because it fits me to a "T". My mind refuses to be bored. I don't watch tv at all. I do spend time on the computer, but that takes more thinking than tv does. I do a lot of word puzzles, usually before falling asleep. I keep a lot of "compartments" in my brain. I like to organize. I think a lot.