Why might a Muslim say the words ‘God willing’ when talking about their future plans?

A Muslim may say ‘Inshallah’ (God willing) when talking about future plans because they believe no good or bad act can come se without the will of Allah. The Qur’an quote, “Misfortunes can only happen with God’s permission” suggests when Muslims face hardships and find their suffering is undeserved they can be aware that bad things will never happen without God’s greater intention.