Lesson #1 Even though you are generally anti-dowel rod (out of shear laziness) you must dowel a four layer add-on or it's just going to tip over.
Lesson #2 Speaking of tipping over, never buy store-bought icing to decorate with again. It's slimy, and heavy and will weigh your cake down.
Lesson #3 Working in a hot un-air conditioned kitchen will only exacerbate the problems caused by not following rule #2, threatening to tear off the north-side ramparts, and make a general mess of all your hard work.
Lesson #4 Never underestimate the good that a half hour in the fridge while properly braced can do for your cake to prevent the ultimate cake disaster from occurring.
Lesson #5 There is no shame in picking up the whole messy add-on and repositioning the ugly-er part to face the back(at least the ugly part is still in one piece thanks to some nicely chilled frosting)!
Lesson #6 Attending church is always worth it(even if it means that there are no tufts of dark green grass piped around the perimeter of castle or climbing roses up the wall or chains for the -slightly disproportionate- drawbridge).
Lesson #7 Your cake will never end up exactly like you envisioned it in your head, but decorating cakes is always a lot of fun.
Lesson #8 Homemade cakes are always beloved by the sweet little children you make them for.
("Who're you callin' little?")