To me, it's a whole set of subtle things. Like whether the pilot out of SNA tells people about the fast takeoff roll followed by the sudden pullback of power for noise restrictions south of the airport, or just says nothing and proceeds with takeoff.

Or whether a pilot apologizes for an uncomfortable ride, or just chimes the seatbelt light and curtly says "take your seats please."

Or whether the pilot is outside the flight deck before and after landing to greet or say thank you, or stays on the flight deck the entire time.

Little things like these give me an overall impression about whether the pilot is focused only on their little area of the flight deck...or is continually conscious of the fact that they have hundreds of human beings behind them, depending on them every second of every flight.

It's my perception that openness, transparency, ability to apologize, and extended communication all contribute to trust.