I'm mature when I need to be, for example; the angry customer is yelling at me and getting mature, this would not be a mature time to burst out laughing or tell them they have lectuce stuck between their teeth instead I simply stand there being apologetic and polite and gently telling them to STFU!

I'm immature at all other times, I did the mature thing, I went off and got engaged and everything now look where I am? RIGHT BACK WHERE I STARTED!!!