eeuuw! handbags!
I think D-Alex and bikeaholic actually have the same attitude to mechanics, DIY and shops, just seeing it from either side of the counter.
Bikeaholic - you're obviously a skilled, competent mechanic who sees the balls ups made by ham-fisted DIYers. D-Alex is a skilled competent mechanic who sees the balls ups made by ham-fisted LBS staff.
Many LBS staff are enthusiastic cyclists who want to stay close to the sport. That doesn't necessarily mean they thay are any good with a spanner, or even like mucking about with allen keys and grease, but they do, nevertheless often end up spannering the bikes, coz in a busy shop its all hands to the pump.
Some of these kids will develop the right attitude and temprament and understanding to become a good mechanic. Others will always remain brutes with a spanner.
Perhaps D-Alex whas using too broad a brush when he feels all LBS will trash your bike, but I like generalisations, coz there's always a truth behind them and they often cause spats!
Stew