I don't tend to describe myself as a Calvinist very often.
Depending on what you mean by the term, I probably am one - I think that Calvin's description of how people are saved (his soteriology) is basically the same as what the Bible teaches, and I therefore agree with it. I think Calvin was a very clever bloke and a very gifted Bible teacher and systematic theologian. That doesn't mean I agree with absolutely everything he said, or that I think the fact that he said it settles an argument, but it is definitely worth reading what he said and wrote.
One reason I don't like the label is that it smacks of putting human views about God above worshipping God (in a depressingly 1 Corinthians 1:12 way). But that's not what I'm writing about today.
What I'm writing about today is the way that “5 point Calvinism” is often badly misunderstood to the point where the label “Calvinism” is often understood to mean something very different from what Calvin actually thought.
Calvin died in 1564, but after his death a big argument developed between people who mostly agreed with Calvin and a chap called Arminius about how people were saved. This led to a big meeting called the Synod of Dort, which ended with the Calvinists agreeing on the famous 5 points (in 1619).
Perseverance of the Saints
(Note the TULIP acronym.) Now all of those, when properly understood (and taken in the context of the debate with the Arminians), are really important truths. But each of the catchy titles is so vague that it is often misunderstood and taken to mean something it shouldn't mean at all. So some people think they are Calvinists, when actually they're nutters. To protect against that, I think it would have been more helpful if they'd stated stuff like individual responsibility as well, so it didn't look like top-down systematics rather than bottom-up systematics. I know too that a lot of people who described themselves as Calvinists after Calvin's death went a lot further than Calvin did, and I'm not sure if those who attended the Synod of Dort were among them. It's possible that what I think is the correct interpretation of the 5 points isn't actually what they meant by them at Dort. But I'm fairly sure it's what Calvin (and a lot of modern Calvinists) would have meant by them, if he'd said them.
And that's why I don't describe myself as a Calvinist, because what people think Calvinists believe is some distance from what we actually do believe.
What it should mean: Total depravity means that everything we do and every part of us is affected by the fact we are sinners. We can't do anything that is totally pure and therefore we cannot earn God's favour.
What it shouldn't mean: Total depravity is often understood to mean that people are as bad as we can possibly be, and that we (especially non-Christians) can't do anything good or right. And to be fair, that's what the label sounds like it means too. But it's not what the Bible teaches; it's not what Calvin taught; it's obviously false.
What it should mean: Unconditional Election means that we can't earn God's favour or make God choose us. His choice is free and sovereign.
What it shouldn't mean: It doesn't mean that you can have someone who desperately wants God, but finds themselves cut off from him because he hasn't chosen them. It doesn't mean that what we do doesn't matter either, or that God treats the Pol Pots of this world the same as the Mahatma Ghandis.
What it should mean: Limited Atonement should mean that Jesus died for the sins of anyone who repents and turns to him, but not for the sins of everyone. People aren't just automatically forgiven because Jesus died – there is a need for individual repentance and faith – but anyone can be forgiven if they repent.
What it shouldn't mean: It shouldn't mean (and Calvin very clearly doesn't mean) that Jesus only died for the sins of a certain clear group of people – the “elect”, so that there's no point trying to reach those who aren't elect. Jesus, Peter, Paul (yes, and Calvin too) were very keen on evangelism – telling people outside the Church to turn to Jesus and trust him.
What it should mean: Irresistible Grace should mean that when God draws someone to him, he does it in such a way that it transforms their desires as well.
What it shouldn't mean: It shouldn't mean that God brings people to him against their will, kicking and screaming.
Perseverance of the Saints
What it should mean: It should mean that nothing the world or the devil throws at those who trust Jesus can stop us from following him. Once someone really has come to trust in Christ, they keep going. Of course, the NT teaches in a couple of places that the key sign that someone has really come to trust Christ is that they keep going...
What it shouldn't mean: It isn't grounds for complacency. It is quite clear that there are people who can look as if they are “in”, who then subsequently show that they weren't. So just because someone “prayed the prayer” 20 years ago, means approximately nothing for whether they are or aren't following Jesus today, and whether they are saved or not.