This is one of those ideas that sound perfectly reasonable but are not.

For some reason, it had all seemed perfectly reasonable at the time.

From his point of view it's a perfectly reasonable story.

The drive was only an hour or so; it would be a perfectly reasonable thing to do on a July night.

Or, of course, it can be seen as perfectly reasonable.

Which was perfectly reasonable, since I'd brought the whole thing on myself.

It seems to me that is a perfectly reasonable position.

"And I think it's perfectly reasonable to want to see the house."

It had all seemed perfectly reasonable and appropriate last night.

They may have been perfectly reasonable and important to them.