At an intersection you wanted to go left and it said Left turn YIELD on green so you just waited until the cars cleared so you could turnthe light had been red for about 7 sec?
You didn't say WHERE you were waiting, so I have to provide you with TWO answers:
1) If you were waiting behind the limit line, the light turned red, and 7 seconds later you made a left turn, you've made an illegal turn.
2) If you were waiting beyond the limit line, with so much as your bumper hanging over the limit line, but ideally, with your vehicle at least 1/4 of the way into the intersection or more, YOU HAVE THE RIGHT OF WAY against traffic that is running perpendicular to you no matter how long it takes the oncoming traffic to clear the intersection so that you can complete your left turn and clear the intersection. It doesn't matter how long your light has been red, you OWN that space until you can complete the turn. That is the law in most states, to the best of my knowledge.
Do not confuse this "LEFT TURN YIELD ON GREEN" situation with blocking the intersection when your intent is to go straight ahead. If the traffic in front of you is so congested that you can not clear the intersection quickly, then you should never have entered the intersection in the first place.
Do not confuse this "LEFT TURN YIELD ON GREEN" situation with a sign that reads "LEFT TURN ON GREEN ARROW ONLY". The majority of drivers in my state do not understand the difference between these two signs.