Once in a while you want to keep track of the dates and the users that confirmed something. Keeping track of dates on row level is a practical application of ModifyRows(). However if you simply use the basic formula, it looks ugly with a comma in front of the first item.
Below the ugly and three correct formula variations, up to you how you like it. However as you can see, the application of the The Last only works well with the The Straight Variation
By using IfBlank(List()) you avoid the ugly comma in front of an item.