100 denarii is effectively 100 days labor - so the third lesson is that we often can make some restitution for our own sins against others.
"Began to choke him" - this is assault, not appropriate for a normal monetary debt. Even on a human level, our retaliation for sins against us tends to be disproportionate. That is why Moses said "an eye for an eye" - disproportionate revenge was prohibited. But Jesus calls for an even more radical approach. "The LORD your God will raise up for you a prophet like me from among your brothers. You must listen to him." Deuteronomy 18:15