Poor bastards though. These days it could've been any of us.
I agree that any one of us has the potential to forget to do something like raising (or lowering) the gear, leaving the speedbrake out or any other task that is part of the everyday of airline flying. The professionalism of the job means that there are two pilots and the checklist is not a bedtime story but a confirmation that an action has been done or not done. Mistakes, or errors are always made but they should be caught by individual pilots cross checking the actions of the other. The consequences can be catastrophic such as not putting the gear down (PIA), not setting the bleed switches properly (Helios).To just dismiss it as "@#t happens" suggests a misunderstanding of why two pilots are needed.
Something I've learnt is to never miss an opportunity to run your eyes over the flight deck. Even in busier times such as below transition, there's always 5 or 10 seconds to have a glance over switches or items that you may have missed even if those things have just been covered in a checklist.
That right there is a get out of gaol free bit of advice.