My worst habit that I have is having to yawn right after someone did. It creates a domino effect when one person yawns another person has to. This is an example of mirroring without even noticing that is what we are actually doing. Mirroring someone allows us to bond, this shows a sign of trust and empathy around the people we tend to mirror.
An example of this is hanging out with your friend or with your significant other for a decent amount of time where their word choices or body language changes to yours. You start to bring a piece of them in yourself. As B.F. Skinner said your environment truly impacts your behavior. We do not notice that we pick up these patterns from them because we are mirroring them.