Oh there are so many things!!!
1. every hot kiss between Lana and Clark (season 1-5)
2. Lana's car crash, Joanthan died etc. (in season 5)
3. Clark kumped from the bridge to save Lois and Lucy (in season 4)
4. as Clark save Lex as he crashed from the bridge into the water (in season 1)
5. Lana's strip (in season 1)
6. Clark who is crying in Martha's arms (in season 5)
7. as Clark tell Lana his secret and than as she say yes (In season 5)
8. as Chloe is watching Clark catching a car (in season 4)
9. as Clark catch the car before it hits Chloe (in season 5)
10. Clark fly and save the world in "Hidden" (in season 5)
11. as Lana run into Clark's arms in "Hidden" (season 5)
as Jor-El talk to Clark through the ship (in season 2)
11. as Jonathan saved Clark as Clark had been shoot with kryptonite ( in season 3)
12. as Clark stopped the bus (in season 1)
13. as Clark sneezed for the frist time in his whole life and blow the door away (in season 6)
and many more....
i will have to go with
"when lana died"
when it happened i was like..
finally no more "Deus ex machina" mind wiping plot retardedness, they just removed her altogether..
then we get the jor el "deus ex machina" of course.
i groaned after the first time they used "i got bumped in the head, and i forgot the last 2 weeks of my life" as a plot fixer....
the term for this i believe is deus ex machina,, where the writers make up some cheesy thing to get away with obvious mistakes and problems