"Meditation is properly done when one feels happy and joyous at the end."
-from volume 4 of Paul Brunton's notebooks Meditation and the Body, ISBN 0-943914-18-3. Sensei is quite happy about the opinions and observations found here. These are older books, he died in 1981, was quite a prolific author, had traveled to India and became a yogi. The notebooks are available for free reading online at Paul Brunton.org
Many of the recent books on meditation depend on scant research and even less experience so haven't much to offer a seasoned practitioner, when she finds one who has both background and research and the information offered is consistent with her own experience she is quite happy to share it.
Google him and check out the book. Meditation is not a wandering-bumbling, on again off again kind of entertainment and relaxation activity. It is an athletic practice of mind-body-spirit. We can and should be efficient in practice, for as the verse to end a day of practice states:
wake up! life swiftly passes by, this is the only moment, don't miss it!