I've known some devout and prayerful Christians who have seemed unhappy the entire time I've known them. They seem down or complain even about everyday ups and downs (chores, work issues, relationship issues (family/partner/friend, etc), unsatisfied with where they are in life). Some can be draining. They have not been diagnosed with depression.
Why is it that so many Christians are unhappy and seem dissatisfied?
Being grateful and thankful doesn't come naturally for people. It's actually something you have to work on.
It's easier to think that God will save you and bring you to heaven for eternity, than to trust God in your everyday life. It makes no sense obviously, but A LOT of Christians are like that. Including me in the past.
So if you don't think God is with you, or listening to you, or that you matter you're going to take more of a survival mode type of attitude. Sarcasm, bitterness, etc are coping mechanisms.
I also think Christians themselves can be quite hurtful in their words to other believers which makes people feel more alone. For example "how are you?" We all know the proper answer even if it's not true. But it should be different with a Christian and often it's not.
People will also complain bc of anxiety or fear. If they are introverts and just need to talk about something. I use to do this when I cared to impress. Now I like the silence. 😆
Some people really are going through hard things. Church can be more like a business than a house of God. Go in, do your job, etc. How can we bring more people to church? Idk I thought we could just eat and talk for a little.
So I can really see both sides of it... people need to be more grateful, but you have to work on it. You have to feel loved by God, also hard for us. People don't realize complaining is a sin. What you're doing God isn't good enough. People would rather feel like victims than to take control and ask God for something else or to just be grateful of everyday small things.