During the preliminary Meetings:

"You're running [insert ERP name here]? Our product can talk to that already. We won't even need to do any testing."

Come 'Go live' Day:

"Oh shit! It doesn't work!"

Three weeks Later:

"We found the problem. You never told us that your implementation of [insert ERP name here] uses [insert any standard feature of the ERP here]"

Post Mortem:

"Sorry guys. I guess the technology has not yet matured to a point where Business 2 Business integration can operate seamlessly WITHOUT ANY TESTING WHATSOEVER. We'll have to keep shrinking the budget until you eggheads get it right."