How do I filter just one Excel column without affecting the rest of the spreadsheet?

Question

I've added a filter on just one column in an Excel spreadsheet but for some reason when I start selecting criteria to filter entities in the column, the entire spreadsheet is changed to those filter settings. I only have the filter set on just the one column, the rest of the columns don't have a drop-down filter. Is there a trick to get the filter to only apply to the one column it's placed on? (If I'm on the wrong Stack Exchange site just let me know if there's a better one, I went through the list and didn't see anything that was a good match).