hehe I had one of our shop accounts call and yell at me because i gave him a 30 minute ETA and I laughed and said ya know the longer you keep me on the phone screamin the longer your eta is going to be 
then he apologized it was pretty funny
MC work does that.. I think it starts with the MC.. There dispatcher looks for the cheapest provider,Which takes time then they call the next cheapest...Until they get someone to cover the call...Meanwhile the customer is waiting..
You get the call and you are already behind 5,10 15,min..or more.....
So when you call customer to give them your ETA they get upset .. Thus the preasure moves to the dispatcher to get the call covered...
Then another MC call and another come rolling in...
You as a dispatch try to get the calls covered.. Then your driver calls in and says "I am LOST !" or "I am out of fuel"
Mean while the first MC call is still waiting...
The sad part is we dont get paid what we are worth to deal with this....
Thats why I dont do MC work... Will deal with them for my rates only...And I take full control over the call.. I call customer and give a REAL ETA....
Its a tough job and you need to relax and be HONEST with the customer....They pay for there roadservice.. You do MC work so you agree to do the low cost service....
SORRY but you signed the contract.. So you have to make your Rates higher to make it worth doing MC work or get out of doing the lower end of towing...
I have tough days to, but I am getting retail rates so it makes it easyer...
Good luck and be safe..
Tim