Of course not all fathers do have a positive impact on their children's lives; tragically for far too many people their fathers (whether by their presence or their absence) cause mental, physical and emotional damage. And so we need to be aware, as we do on Mothering Sunday, that Father's Day is not a day of celebration for everyone – many people do not want to celebrate their fathers, and other men may have had children who died or may have never been able to have children despite wanting them.
Trinity Sunday is the day that Christians remember that throughout the Bible God reveals himself to be 'Trinity', i.e. One God yet Three Persons – Father, Son and Holy Spirit. Each Person is distinct from the others (unlike water/ice/steam that can only be in one state at a time) but there are not three parts of one God (unlike a three-leaf clover). The doctrine of the Trinity is more fully expressed in the Athanasian Creed, which you can read either in its traditional form or in a modern version, you can also watch the teaching on the Trinity here from our current Discipleship Service series looking at the Apostles Creed. This is a complicated doctrine to get our heads around, though we shouldn't expect the infinite God to be easily understood by our finite minds! The important thing to remember about the doctrine of the Trinity is that it wasn't a result of philosophical thinking about God, but instead was the fruit of experiencing the divinity of the Father, Jesus Christ and the Holy Spirit, alongside the revelation in the Bible of their divinity and also the one-ness of God.
The relevance of this for Father's Day is that some would argue that because some people experience earthly fathers as destructive and abusive, and emblematic of an 'oppressive patriarchy', then we should not refer to God as Father. In other words, for some the Trinity is 'triggering'. However, it is precisely because our earthly fathers (and we ourselves if we are fathers) are fallible that we need to hold on to the Fatherhood of God.
The doctrine of the Trinity reminds us that God the Father is eternally Father - he is the original prototype of fatherhood. He didn't look around for metaphor to describe himself and choose 'father', instead he shaped human society so that earthly fathers might give us a glimpse of him. So our experience of earthly fathers, whether positive or negative, should propel us to seek out our perfect heavenly Father.
So however Father's Day makes you feel, seek out the Father who loves you with a perfect love. To do that, come to the Son, Jesus, who said “I am the way and the truth and the life. No one comes to the Father except through me” (John 14:6).