OK now. I got my first flat on my new road bike and had to take the wheel off to change the tube. My old bike was a mountain bike with vertical dropouts. So putting the wheel back in was simple, as gravity holds it in the correct position. New bike has horizontal dropouts which I didn't really think about before. I got the wheel back in fine and put it into the dropout as far as it would go and tightened it up. But wouldn't the position in the dropout influence how right the chain becomes and hence other factors?
Did I do the right thing?
Logic also says to me that with horizontal dropouts you need to be more careful with making sure you tighten the wheel back on nice and firm.
What are the advantages of hoizontal dropouts again?