Excessive, ridiculous, out-of-bounds, over-flowing, beyond abundant.
That is the kingdom of heaven.
Mustard seed - this teeny seed turns into a rough, dry looking small shrub, that spills many many seeds around it to propigate new plants. How can this become "the greatest of shrubs and becomes a tree, so that the birds of the air come and make nests in its branches." This becoming of a small humble unwanted weed into something grand says miracle, and how God starts works with the small and humble to make his kingdom known.
Yeast mixed in flour - the absurd amount of bread made by the woman reflects the abundance and fullness of the kingdom
Treasure hidden in a field -great joy in discovery and overwhelming response to that joy that the kingdom inspires.
Pearl of great value - selling everything in order to obtain that which is precious. That is how important the kingdom is for us.
Net thrown into the sea - everyone is drawn into the kingdom, none are left out of that net. It is only at the end of the age that the separation comes. All are given the invitation, all are given the chance.
The great irony in this story is that Jesus asks his listeners "Have you understood all this?" and they answer "Yes."!!!!