I realized that each in and out cooks thier burgers differently. The best burger i had from in and out at the one in costa mesa. The one in marina pacifica would be too salty but i believe they fixed that problem and it now taste like all the in and out.
Even the fries are cooked differently each time. Sometimes you get toasty fries and some times you get a good batch that makes you want to order more.
Therefore, give in an out another shot. Maybe try another location. You said that they were busy. Try it when they're not?