I never liked setting treated posts in concrete, saw too many over the years that were that were rotted off at the top of the concrete.
I agree and although you'll likely never have this problem, but in cold temperature areas winter frost can heave the concrete thus causing the poles to rise a bit.
I put lots of rocks in beside these cedar 6 x 6's that were sunk two feet in the ground, pounded the rocks in and around and then put smaller rock/stones in, levelled everything and nothing has moved even 1 inch in 2 years now.
All is level and even, photo causes poles to look angled.
