Catching other people's expressions

I have long noticed that I am very quick at picking up other people’s expressions. Something quite common if you spend a lot of time with someone. What perhaps is less common is the fact that I can still use some those expressions for quite a while afterwards. Two examples come to mind – one from V when we were in high school, and that I have noticed she hasn’t used in years (and I still use it); the other was something quite irritating that RB picked from her then boyfriend, and that I started making fun of and ended up adopting it for a while against my better judgement (dropped that one now, thankfully).

However, the opposite isn’t true – I’m not as catchy… So, I was a tiny bit surprised and amused when my flatmate yesterday repeated something I say quite often while speaking to someone else.