Paypal's post login page comes to mind.
I want to see the dashboard after login, not a uninformative ad that probably took time and money to put there.
My PayPal was put on freeze a few weeks ago. When I called to get unlocked I was told the verification lock was put in place because perhaps (they couldnot say exactly) because I had started some Capital Loan process they have. Really, what had happened was I clicked that damned interstitial ad post-login.
The forced ad, accidentally clicked, locked my account, had to spend an hour cleaning it up.