Status quo bias
Many people do not like to try something new, even if the alternative is better. Status quo bias is an emotional bias when people want their familiar things to remain approximately the same, compared to the alternative. Along with the accompanying biases, people perceive the damage from losing the status quo as greater than the potential benefit of the alternative.
How can this be applied?
Do not redesign for the sake of redesign. If people use something successfully, then do not stress them. Try to solve their problems. Bring changes only if the new solution will benefit people. But do it gradually.
The same can be applied to various design solutions. If there are already accepted conventions, and people are used to them – do not reinvent the wheel. Keep the status quo.