Memories fade. Details get forgotten. And sometimes, flight attendants don't get paid for the work they perform. I'm talking about Holding Time, one of many reasons why you should always log your trips.
I use a computer program called Outlook to store my trip data. But you can easily log your trips without a computer. Try the following:
When you are sitting in briefing, make a box on your ID or FLTLOF:

Then, during your trip, note any holding time details. Do the same for Understaffing.
Then:
And don't just always log the FLTLOF, ID, and payment details. Also log unusual incidents/events that happened. This is especially true if you are a Purser. You never know when Mrs. Crabtree in 35G might decide to file a lawsuit claiming 'soft cell tissue damage' sustained on her head when a golf club fell out of the overhead bin because the dumb ole flight attendants weren't stowing them properly.
It's even helpful to log hotel details at Hotel Flight Attendant, layover location information, Duty Free sales, Unimatic tips, etc... Organize it. File it. And when needed, you'll have it all there.