If you love someone, you generally want to be close to them, to be in relationship with them. So if there’s a God and if he loves us, wouldn’t he want to do the same with all of us?
But there are some people who don’t experience God that way, even though they want to. So doesn’t this show that a loving God doesn’t exist after all?
An argument along these lines asks some interesting questions but doesn’t seem to be as strong as is sometimes claimed.
God may have good reasons, like giving us freedom of choice, to not make himself overwhelmingly obvious. And, christians believe, it is only a matter of time before he does make himself more obvious.
And of course many people feel that God is quite obvious to them.