Altar calls

So, I don't usually like to pick at church services, because I know each one is different and no one is perfect, but one thing I've never really understood is altar calls. I'd love to know where this tradition came from and why. I mean, it's totally great for someone to step out of their comfort zone and make a statement about their desire to turn their life over to Jesus, but why should it happen in a setting where the pastor is talking over some emotional music after the sermon, almost guilting people into coming up the front. I guess some people need this encouragement to actually make the decision and get someone to pray with them, but I'm sure a number of people must go up because they feel obligated to.
Don't even get me started on being asked to raise your hand if "you're making this decision today and want to be prayed for". I definitely don't get the point in that one. It always makes me think that speakers who do this must, in some way, gauge the success of their sermon by how many hands are raised. And they always say "thank-you" to the people that do. Why?
Anyway, that's just what I think. And I welcome any input or opinion. I definitely think having people come forward for prayer has a valuable place in church services, especially because it may be the only opportunity they have to get someone to pray with/for them, and often making that move out of your seat in front of everyone is powerful for people and I'm sure God honours it... but I just don't think there needs to be all the hype and emotional triggers that often surrounds it.
There you go.