TableCellRenderer sets color to many cells and not just one

I have a JTable, that I want I want to be able to change the color of a single cell that is clicked on.

Here is a simplified version of my code:

public class TableFrame extends JFrame {

    public TableFrame() {
        JTable table = new JTable(8, 8);
        table.setGridColor(Color.BLACK);
        table.setDefaultRenderer(CustomCellRenderer.class, new CustomCellRenderer());
        getContentPane().add(table);
    }

    public class CustomCellRenderer extends DefaultTableCellRenderer {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            JLabel l = (JLabel) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            if (hasFocus) {
                l.setBackground(Color.red);
                l.setText("Hello");
            }
            return l;
        }
    }
}

When I click a certain cell, I expect it to change color to red and add "Hello" to it. It changes the text, but for some weird reason, it changes the color of all the cells after it? And when I click an uncolored cell, it does the same, but not always in an organised way if that makes sense? Like, it won't color all the cells after it, but maybe some that are just above and leave others blank..

It's really weird and makes no sense whatsoever. What is happening??