Keeping it short and sweet today, the sixteenth chapter of Proverbs basically says the same thing throughout:
You can make plans.
Sometimes you get in the way of your plans.
Sometimes others, such as those in authority over you, get in the way of your plans.
Sometimes everything flows perfectly.
In every case, the Lord is in control.
It may be that He allows your mistakes and missteps to detail your plans, or He sends someone to block your path, or He keeps all of that from happening to let your plans succeed.
No matter how much you scheme, wink at the right people at the right time, or surround yourself with faithful helpers, if you are not relying on God, your plans may very well be worthless.
Trust God to guide you, and your plans will become His plans. Or at the very least, you can more easily handle when plans seem to change suddenly.
Take a few minutes to read chapter 16. You will see how much Good has told us.