-It's too dark
-It's too late
-It's too windy
-She just ate (how long do you guys wait?)
-It's too close to feeding time
-It's too muddy
-It's raining, or thundering, or lightening...
-She's in season
-She just had her teeth done
-It's too cold
-It's too buggy
-It's too hot
Ok, I might have forgotten some others...haha, add em if you got them and debunk the others!