Have previously bought a specific lingerie set for a regular (reasonably priced high street/department store stuff, not overpriced Rigby & Peller or Agent Provocateur), but that's as much for my pleasure (even though, granted she will use it with other punters - then again, she has bought herself specific outfits at my suggestion - again, I'm sure other punters will appreciate them). It added to my experience, and it's not like I make a habit of it.
If I'm seeing someone who's got a flat near a supermarket that charges for parking (£5 for 3 hours), then I don't see the harm in picking up a box of chocs/reasonable bottle of wine. Don't do it all the time, but basically, you catch more flies with honey than you do with vinegar, so I don't see the overall harm, as long as you keep a sense of perspective.