It happens. I know because I did the same thing. Several years ago I had the brakes in my 80 replaced by a shop in Cary. They put on cheap aftermarket rotors and charged me about $1300 for all four corners. The rotors warped within a month; I wanted it looked at by another shop. Since we were new to Raleigh at the time, had no garage, and I needed my truck back ASAP, I made the grandiose mistake of taking my truck (a Lexus LX450) to the Lexus dealer. Special note: Don't do this. I'm pretty sure they saw me coming a mile away. I was charged $670 to have them resurface my brake rotors. The truck was back to normal, but not for long.Feels bad to be taken on such a ride for minor work.
About a month later the brake pedal started to pulse under braking again. I took the truck back to the shop that did the initial work and told them what had happened. The owner of the shop told me I was an idiot for taking the vehicle to have its brakes resurfaced at the Lexus dealer...he was right. They helped me out a little bit though. The truck needed new tires, so he was willing to mount and balance new rubber on the truck for free. I just had to send him the tires. There is more to the story, but I don't want to hijack this thread. Suffice it to say that I do my own brakes now.
The moral of the story is, everyone makes ill educated decisions every now and then. Nobody is immune to it. Learn form it and keep going.