his vision was less than perfect, thus he didn't qualify to become a pilot. i think there's no sarcasm in tat sentence.

his love for her was less than perfect; he was always buying her gifts and flowers.

His vision was less than perfect, thus he didn't qualify to become a pilot.

I think there's no sarcasm in that sentence.

His love for her was less than perfect; he was always buying her gifts and flowers.