Women sometimes do this thing where they meet an acquaintance, think he's cute, and find opportunities to hang out with him, watch him, and evaluate him as a potential mate. Then presto, by the time they're done evaluating him, he's become integrated into their social group too closely for the girl to be comfortable asking him out because it'd now be awkward if he rejected her and all her friends found out. It's kind of the female equivalent of the stereotype-based-in-fact where men see a beautiful girl and immediately talk themselves into thinking she's out of their league and it'd be the end of the world to get humiliated by a rejection from her, so they might as well not even say two words to her and just keep standing over here awkwardly in this corner.

The annoying thing about the female version is, 99% of the time, the acquaintance-level guy would have accepted a date or at least been totally cordial and flattered if he did have to turn the girl's offer down, and if he then became a friend, it wouldn't be awkward at all--it'd have been just part of the story of how he became a member of the social group.