Exodus 11:1 KJV
And the LORD said unto Moses, Yet will I bring one plague more upon Pharaoh, and upon Egypt; afterwards he will let you go hence: when he shall let you go, he shall surely thrust you out hence altogether.
I am not sure a person could say that each plague was progressively worse than the previous but I am sure that the last plague was worse by far than anything before.
I think people tend to think they can "handle" a few little plagues from God. They understand there are consequences to their actions and, whether they would acknowledge those consequences come from God or not, every person in some way calculates the risk and chooses the pleasure of the action over the consequences to the action, or not.
· The loss of a certain amount of money in gambling
· The headache the morning after a drinking binge
· The night or two in jail getting caught in a theft
On and on it goes with actions we know to be wrong and risky, but we figure that we might get away with it and, even if we don't, we can handle the consequences. The trouble is, without our realizing is sometimes, those consequences are mounting up and their will come a time when God says, "Yet I will bring one plague more." and that one will be too much to handle. That one will cost us far more than we imagined. That one will break us.
Whether we can handle the consequences of our actions or not if we continue in defiance of the clear teachings of the Word of God, there will come a plague, a consequence that is more than we can bear. The thing to do is learn God's Word and follow Him obediently.
That way we never have to look out for the one last plague.