[roldie]

There was a great talk at SXSW last year entitled "The Myth of Reducing Friction in your Product."

Basically, within a given flow (say onboarding or signup), you want to consider having some points of friction interspersed with low friction points. Adding friction in the right places helps to create users who will a)come back and b)will be more active users. The speaker presented some data to back up her assertions.

Getting back to OP's point, the emotional experience is a point of friction that may be worthwhile. Though it may slow down the conversion process or whatever flow the user is supposed to go through, it may result in users who become more attached to the product and ultimately spend more.

http://schedule.sxsw.com/2015/2015/events/event_IAP35677

[wtetzner]

The thing is, if the site doesn't make it easy for me to accomplish what I want, then my emotional response is frustration. It doesn't matter how nice or pretty your site is if I get frustrated before I have the chance to appreciate the design.

I think trying to evoke a certain emotional response can really only be effective if it's not getting in the way.