You have never picked a ripe blackberry.
I have never picked a truly ripe blackberry.
No one, in the history of the world, has ever picked a truly ripe blackberry.
When a blackberry is allowed to fully ripen on the cane, the slightest bump will send it tumbling to the ground. If you approach it very carefully, and in one quick motion grasp both sides of the very ripe blackberry with equal pressure, you will be rewarded with a sweet sticky mess on your fingers. Licking off your fingers will make every other blackberry you have tasted pale in comparison.
There are two kickers, of course. Visually a truly ripe blackberry looks very much like an almost ripe blackberry, so you never really know when you will get one. Once the berry starts to dry out and look leathery, it is overripe. It still will make a decent tea, though. The other thing is that if you use gloves to protect your fingers from the prickles, the effect is not nearly the same.
The larger point is that you will never have this experience unless you are out there in the blackberry patch picking berries. Okay, maybe a really good friend will let you lick his or her fingers, but you still have to be out there with him or her. A pack of berries you buy will never have ones quite that ripe, even if you get them from a farmer's market. And while you can buy the blackberry bushes to plant, chances are good that if you live in an area where blackberries do well, some bird will come along and deposit the seeds naturally. Once you get a number of these, you will probably want to only keep the best and cut out the rest, as I have done.
On the Long Ascent, you can find, for free, simple pleasures that are better than any you can buy.