I can't get past it.  I've tried 50 times (probably).  I make sushi ahead of time, cones ahead of time, smoothies ahead of time.  I try to use the radio.  I try (but can't always) do chains, what else?  Please, I'm losing my mind!!!!!

Have you upgraded the ovens to the highest level...and are you clicking on the buttons to fully charge them up...
 
It is important in this level to seat the impatient ladies and the bodybuilders quickly...the hippie people upset the impatient ladies...but they themselves are patient when they are seated...I seated by color the impatient ladies first paired with the bodybuilder guys..then the hippie folks...used music to keep the old men patient...I rarely have used the hot sauce or coffee and have completed the game with expert on all levels except the final one...I am still working on those expert levels...
 
You have to get all of the chairs up to 4...so that when you seat those last customers...which should be none of the impatient ones...you get great color bonuses...and full happiness...

Have you upgraded the ovens to the highest level...and are you clicking on the buttons to fully charge them up...
 
It is important in this level to seat the impatient ladies and the bodybuilders quickly...the hippie people upset the impatient ladies...but they themselves are patient when they are seated...I seated by color the impatient ladies first paired with the bodybuilder guys..then the hippie folks...used music to keep the old men patient...I rarely have used the hot sauce or coffee and have completed the game with expert on all levels except the final one...I am still working on those expert levels...
 
You have to get all of the chairs up to 4...so that when you seat those last customers...which should be none of the impatient ones...you get great color bonuses...and full happiness...

I'm stuck on this level too.  I have all the speed upgrades and cooking boosts... but I just can't seem to serve fast enough OR keep color combos going.

Anyone have a seating plan?  :)

I just played this level again and I used the hot sauce and the coffee and the blue jutebox and here's the seating chart I used
 
blue
red
yellow
purple
green
yellow