Oh dear, The Mentalist ended up being a bit of a disappointment. It started going a bit downhill after a while but season 6 was an absolute cluster****. The climax to the main Red John storyline was such an anti-climactic letdown in every sense. Someone really didn't know how to pay off a story arc. Red John turns out to be... some random dude we met once early in season 1 (I couldn't even remember the character). All that stuff with the Scientology-like religious cult Visualise and the insinuations RJ might be connected to it or even its leader (the great Malcolm McDowell who excelled in a recurring role, only to be completely thrown away and wasted in the end) turned out to be much ado about nothing.
I liked Patrick and Lisbon getting together in the end (so obvious, and they had way more chemistry than Rigsby and Grace ever did) but it was so apparent they were making this whole thing up as they went, and then totally fumbled the ending, that I was just left going WTF. I can only imagine how peeved those who actually spent years watching it (instead of two months like me) must have felt.
Somebody really needed to watch Buffy or Person of Interest for instructions on how to close an epic story arc in a dramatically and emotionally satisfying manner.