There are many reasons why people have faith, and often it is a search for something bigger than themselves. We look at the world around us and we just know that there is more than we can see. And we want to understand, so we seek for that which can't be proven, only felt.
The thing about faith is that it asks us to be better, and being better is hard. So we find motivation to do the things we feel we should be doing, and that motivation can be rooted in love...or in fear. Faith rooted in love wants you to become the best person you can be, but it also wants other people to be the best they can be. Faith rooted in fear tells you that if you don't behave properly, bad things will happen to you (either in this life or beyond).
Now, on the surface, this seems like a trivial issue. Whether your actions are based in love or fear, it is your actions that matter, right? But when we poke a bit deeper, we realize that love based actions are inclusive. We want better for ourselves, but we also want better for everyone else. There is no need to point fingers or turn away from people who are different from us. The focus is on improving and becoming the best person you can be (and doing your part to make the whole world the best that it can be).
With fear based faith, the tendency is to only work hard enough to not get in trouble. It also creates barriers between the 'good' people and the 'bad' ones. Because some behaviors are sins and considered inherently evil, the people who do them are also linked to evil. And treating someone as if they are evil, just because they do a thing you don't approve of (especially something that might only be considered a sin in your religion...and not in the general world view) doesn't encourage people to grow and be better, it simply makes them feel like they are flawed or otherwise less than.
But a fear based faith also encourages the mindset of 'it's okay if I don't get caught', because it's not about wanting to be better, it's just about not wanting to be punished. This is why so many 'religious' people struggle with the concept of morality outside of their church. It's why we hear things like, "If you don't have religion to tell you that killing is wrong, then people won't have a reason to not kill." Which is a whole scary landmine of an attitude, if you ask me.
I also find that most people who have faith based in fear have a very cookie cutter approach to what 'good' means. There are specific things you can (and can not) do, and there is no wiggle room. Faith based in love tends to be more open to individuality. It doesn't look at an action and judge it right or wrong in isolation, but it looks at the whole situation, it looks at the people involved and asks what is right for these people, in this moment.
Here's the twist: faith based on fear is easier. It's relatively simple and very clear cut. Here is the list of things you Must Not Do! There may be some things that you should do, but fear based faith is much more heavily weighted towards the do-nots. And because it's a list of things, it's very clear cut, so there is no need to think or debate the morality of the thing. Your faith tells you it's either good or bad, no exceptions.
Love based faith requires a lot of work. You have to be really honest with yourself about where you are at. You have to explore those icky feelings that you know aren't right (but you still feel them anyways). You have to push yourself to find the bits of yourself that you don't care for...and work on them. You have to think about situations, with all their nuance and complexity, and determine for yourself, what the best way forward is.
You also have to be really willing to accept other people for who they are. Not who you want them to be, or who you think they should be...but who they are. You meet people where they are, and you work with them, on the things that they are struggling with. You let them be the master of their own ship and guide they way...you aren't there to take over, just to support. And that is a lot harder than just telling them what they 'should' be doing and then judging them for their failings.
I want to point out here, that people can approach the same faith or religion from their own fear or love based perspective. There are Christians who approach their faith from a love based perspective...and Pagans who are fear based. This is about you...and how you interpret the faith you believe in.
It's also not necessarily a black and white thing. You may be love based in some aspects of your faith and fear based in others (the afterlife is quite often a fear based belief). There may be very specific parts of your faith that are rooted in fear. Or maybe you grew up with fear based faith, but it is starting to unfold in a way that is now rooted in love.
Wherever you are in your faith journey, I encourage everyone to take a good look in your heart. Think about why you do things, especially things related to your faith. What motivates you? Where are you acting out of fear, and where are you embracing the love? Where can you turn fear based actions into love based ones? The more we can open our hearts and work on improving everyone, the better the world (and thus all of us, individually), will be.