From my childhood growing up as a non-Catholic I remember hearing the phrase "holy and sanctified" and it was often used in a somewhat mocking tone in reference to our Pentecostal Holiness brothers and sisters. As we see. In today's first reading, Paul addresses his 1st Letter to the church in Corinth "to you who have been sanctified in Christ Jesus, called to be holy."
It is worth noting that he speaks of sanctification in the past tense,"have been sanctified" and then looks forward with "called to be holy."
We are sanctified by the suffering, death and resurrection of Jesus Christ which we are full participants in by virtue of our baptism.
Paul's instruction to us is, then act like it. We are "called to be holy." This call to holiness is a daily call to every Christian. It must be rooted in prayer, daily conversation with Christ, that will then direct our actions.
Being holy doesn't mean constant seriousness and lack of fun. On the contrary, when we truly understand the incredible gifts God has given us we can find beauty joy and fun all around us and we can live stress free. Email lasts for ever. Practically every phone has a camera, and google logs your every search. But if you're living a holy life it doesn't matter. Holy and Sanctified and Happy.