At their best, people will answer rather than comment. Joey comments that almost anything can be used in this manner. Solecki's comment is a good point. Can frequently be used sarcastically. . He was an example of our finest in every way. At it's peak in the seventies, ... At it's strongest In his most understanding times he ....

@solecki Interesting! I was actually trying to use some adjectives in that construction and found out that many of them could be used to imply sarcasm, for example: I'm at my coolest! he's at his wisest! she's at her sweetest!

Thanks Joey!

"... at its finest" is quite commonly used. It's often used sarcastically though, e.g. during a BSOD (basically when the Windows operating system makes a booboo): "Windows at its finest".

We can use almost any superlative with this combination. Some are more common than others, but you could theoretically use any superlative with "at my", "at your", "at his/her/its".