Truthful Thursday - I don't take orders very well

What is the definition of volunteer?  According to the dictionary - a person who performs a service willingly and without pay.  You are probably wondering where I am going with this subject today.  Since it's truthful Thursday, I thought I might as well get some of my venting online.  I am sure you have read somewhere that my MIL and I volunteer at one of our local library.  We spend an hour or two depending on the work required on a weekly basis.  Most of the time we are there, we have fun doing what we think needs to get done.  There are no other volunteers during the day and time that we come in to offer our precious time.  Twice a year, the group that we belong to have a Book Sale.  They also need help organizing the books for the sale the day before and on the day of the sale.  For the past couple of years we have been helping on both days and spend more than a couple of hours each day.  This past weekend the sale was on and again we offered to help.  When we arrived, we noticed there were more volunteers working.  We approached our President to ask what needs to get done.  She instructed us to start filling up the shelves of our NOOK by using some of the books out on the floor.  My MIL and I started collecting the books that we need and as soon as we got to the Nook, one of the other volunteers started telling us what we should do and not do.  Shortly after, a student volunteer who was tasked as a cashier for the sale, also came in the Nook and started giving us instructions.  Both of them came back another time to give us more instructions and ordering us to remove some of the books as they were not in the correct spot.  She was using the words, Real and Not real (instead of Fiction and non-fiction).  I tried to control myself and not say anything because I knew what words would come out.  My MIL was just calm and all I said to the student volunteer "if you seem to know what should be on and off the shelves, would you like to continue and we can leave".  She immediately went back to her post as a cashier.  I told my MIL that we are done for the day.  If they are not paying me to do the job, I do not appreciate being ordered or supervised.  Once I got home and have calmed down, I wrote an email to our group leader.  As Jeff always say "if you are not appreciated, you don't need to waste your time there".