I thought the episode ended really well also. Rick's character is grieving. Even so, Rick feels compelled enough to honor Carl's dying wish and contact Negan. Certainly, Rick's desire to kill Negan is overwhelming but (at the very least) Rick's internal bitterness did not prevent him from telling Negan that Carl had written him a letter--which is something Rick was neither forced to do or wanted to do.
Conversely, Negan's warped sense of priorities compelled him to recite his insane rhetoric about 'saving' people. Regardless of HIS overpowering urge to end Rick, Negan felt a genuine loss hearing about Carl's death. Negan wanted to convert Carl to his ideology and allow someone like Carl to continue his philosophy of 'saving' people after his time was over. Negan rebutted Rick trying to pin Carl's death on him because Negan 'knows' he could have 'saved' Carl eventually.
Two diverse and similar characters fooling themselves. That was a very dynamic conversation between the two of them. Good stuff.