For me my worst flight was from HKT to BKK with TG, on a 744 during the rainy season (in 1998). That day there was a terrible storm but we took-off normaly and from then on during the two hours flight I experienced the hardest (and scariest) turbulences I ever had until today.
Our 747 was going up & down, we were highly shaken and everybody in this flight was really scared. But the friendly cabin crew did their best to reassure everybody. When we landed in BKK I couldn't believe that I was still alive 8O
Despite this, TG is my favorite airline with friendly cabin crew, and comfortable plane.