Why would a guy avoid a girl?

as a girl i woul say that a shy girl would avoid a guy, because she doesnt know what to say around you and doesnt know what youre like. Or maybe, she doesnt want to be around you, but that is usually not that case. If you want to be around her, start up a conversation with her, but make sure you arent the only one talking. something else you may want to try is passing a note to her which would be easier for her than having a direct conversation. good luck