appreciate seeing proof

[kjc0123]

What's the meaning of "appreciate seeing proof" in the following sentences?

He turned and gazed tiredly into the full-length mirror across the room. The man staring back at him was a stranger.tousled and weary.The past year had taken a heavy toll on him, but he didn't appreciate seeing proof in the mirror. His usually sharp blue eyes looked hazy and drawn tonight. A dark stubble was shrouding his strong jaw and dimpled chin. Around his temples, the gray highlights were advancing, making their way deeper into his thicket of coarse black hair. Although his female colleagues insisted the gray only accentuated his bookish appeal, he knew better.

[ursula62]

in this case it means he didn't like how he looked!

In this instance, to appreciate means to be grateful or thankful for something.

[Peter Pedant]

yippee kay jay - reading some pulp fiction, I see. Much better than that constitutional c*ap we were wrestling with.

Proof is an interesting word. To prove something is to demonstrate its truth under oath in court, but there is a related meaning of trying, testing, and this gives rise to the use in

the exception proves the rule, (=the exception tests the rule) or

the proof of the pudding is in the eating (= the quality of the pudding is tested by eating it)

In this extract, the mirror is showing him how raddled, ugly, shot up he is. He doesnt appreciate it -= he doesnt like it.