I bought a road bike from Halfords last year, did the 'reserve online, pick-up in store' thing. Got there (about 15 miles away) only to be told they didn't have a spare one in stock.
To cut a very long, annoying, story short, they eventually (weeks later) got one for me, so I asked them not to build it and I'd pick it up and take it away in the box. The 'top bloke' in there assured me that as I was spending a significant amount on the bike that they would ensure that everything was set up properly, so against my better judgement, I let them build it.
Went to pick it up to see some young lad building another (childrens) bike, with the forks on the wrong way - didn't have the heart to tell him as I was sure one of his colleagues would anyway. Picked my bike up and all seemed well. Made my second mistake, by not check tightening everything before going out on it. I had just descended a hill and was travelling at about 25-30mph and got out of the saddle to honk up the forthcoming incline when the bars and stem decided to turn independently of the fork - luckily it didn't result in me eating tarmac, but I was most annoyed to find neither stem bolt had been tightened. The only thing holding the bars straight was the top-cap.
Idiots