S. R. Faruqi:

Taking this theme a bit further, in the sixth divan he has expressed it like this [{1894,4}]:

mujhii ko milne kaa ;Dhab kuchh nah aayaa
nahii;N taq.siir us naa-aashnaa kii

[I was the one who had no skill/style in meeting
it was no fault of that unfriendly one's]

But in the present verse, the style of sarcasm is very excellent. In hamaare aashnaa there's also the point that the beloveds of others might perhaps not be of such a kind, but exactly this is the habit of our own beloved. In hunar yih hai there's also the point that everyone has one or another kind of skill; the skill of our friend is unfriendliness. By juxtaposing aashnaa meaning 'beloved' to 'strange/stranger', he has created a fine 'opposition'.

FWP:

SETS
MOTIFS
NAMES
TERMS == OPPOSITION

Just to offer another perspective, here's an observer describing Shakespears's Cleopatra (Antony and Cleopatra, Act II, scene 2):

'Age cannot wither her, nor custom stale 
Her infinite variety: other women cloy 
The appetites they feed: but she makes hungry
Where most she satisfies; for vilest things 
Become themselves in her...'

So possibly the beloved's 'skill' is similar: she's not unknowing (that is, cruel or indifferent, refusing to recognize her faithful lover); rather, she's unknown and even unknowable, and thus endlessly fascinating; the speaker might be admiring this quality or art or skill, rather than speaking sarcastically.

I don't know why SRF restricts the 'opposition' with begaanah to the case in which aashnaa means 'beloved'; to me it seems that the dichotomies of unfamiliar/familiar or unacquainted/acquainted or stranger/friend work equally well.

Note for grammar fans: We could also read mile barso;N as a third-person singular future subjunctive ('she might/would meet'). In the context of the verse, reading it as a first-person plural perfect seems a bit more suitable, but neither reading can be ruled out. In this verse, it doesn't seem to make much difference.