Ok, I did it today, first time ever, after ferrying my newly purchased
152 home. I realized about an hour after landing that I'd forgotten. I
called the FSS and they'd informed me that they'd called the tower who
had confirmed my landing and thus the plan had been closed. I felt like
a complete ass.

How big a deal is this? I'm afraid to ask anybody at my FBO. I'm not
gonna get a letter am I??