How can I stay upset when....

Thing 1 comes home having had an antibiotic induced incident at school.  Thing 2 is in different clothes because she literally bit a hole in the first shirt.  Thing 1 runs inside from backyard with liquid poop puddling in his shoes.  While cleaning Thing 1 up, Thing 2 plays in poop to guarantee equal attention for all.  1 bath and third set of clothes for the day later, Mama attempts to clean up kitchen.  Thing 2, upset at being expected to self entertain for even a moment, takes revenge and plays in poop one more time.  Put her in tub.  Thing 1 now has another explosive moment.  While dealing with him, Thing 2 explodes in the bathtub water.  At what point is it acceptable to start crying.  Get Thing 1 and Thing 2 cleaned up yet again.  Thing 1 smiles at me and says "I'm really happy you are my Mama."  Thing 2 nods vehemently "YES, YES"  I guess there are worse things than poop.  But prayers for cleaner days still accepted... please.