This idiom means failing because you try to satisfy two choices at once. The picture of missing both stools explains it well.

In person and in-person are both correct, but they do different jobs. One is a phrase, and one describes a noun.

A while and awhile sound alike, but they work differently. Learn which one fits after a preposition and which one stands alone.

“Geek” once referred to a carnival performer, later an odd person, and now often describes someone deeply enthusiastic.