Accrued expenses are costs the business has already used but not yet paid for. The coffee shop's baristas worked the last week of December, but payday falls in early January. The shop has already received that week of work, so it owes the money even though no bill or payment has happened yet, and that debt to the staff sits in accrued expenses at year end. The same applies to electricity used before the bill arrives, or interest building up on a loan between payment dates.
The reason accounting records these is fairness between periods: December's accounts should carry December's costs, whether or not the cash has left yet. For reading the company, this is a routine line. Only a sharp unexplained jump or drop deserves a question.