What are some of the common misunderstandings you see year in year out?
Immediate rush to select start switches to CONT in slight turbulence. Using autobrake when runway length and surface conditions obviously don't require immediate braking on touch down.
Relying on the cabin altitude warning at 10,000 ft (if not pressurising after take off) rather than checking the cabin rate of climb indicator to confirm pressurisation is taking place normally with this check being done as part of the after take off scan.
On hearing the 60 knot call by the PM during landing, lowering the reverse levers full down quickly causing aircraft acceleration as the reverser panels close leaving the N1 passing 60% on the way down to idle. Failure to read the FCTM which discusses the correct method of going to idle reverse.
Relying heavily on using Supplementary Procedures section to remind pilot how to crossfeed and how to do the necessary switching for engine bleeds off take off and switching to normal bleed config after take off. This is elementary systems knowledge and should be known without resorting to a `cheat sheet`.
Using excess control wheel offset for minor crosswinds on take off when no offset is necessary in the first place. Relying blindly on the PM call of "rotate" before commencing rotate instead of rotating at the VR speed on own ASI bugs. "Following" through (pushing) with hand behind thrust levers during other pilots autothrottle take off. Quite unnecessary and annoying to PF and can cause damage to AT clutch system.
Inability to use commonsense in pilot induced oscillation when hand flying on final. Simply relax death grip on controls for less than a second and aircraft takes care of itself.
Being persuaded by twitchy captain that practice manual flying is dangerous even though weather and ATC conditions are ideal.
Questioning every decision by the captain to make a point you are a team and it is your "Right". In other words big noting yourself and scoring points fuels your ego.
Not keeping an eye outside looking for traffic in VFR departures and arrivals but instead keeping heads down and relying 100 percent on TCAS for initial warning. There are many more but other Ppruners will surely add their own.