This works for romance/sex, too. Have a hard wall on how far you'll go, and only move it when you're alone and calm. When you're in the heat of the moment, keep in mind that you can move it when you're alone and calm. You can even intend to do so -- and if when the time comes, you still think so, there you go.
Having that pressure release helps actually stay within the bounds you set. Otherwise it requires a great dal more patience.
It took me some effort to link "this" to "never buy when you're in the shop" :)
In a New York shop, I once got pressure-sold something expensive I didn't really want; when I said it cost too much, I was asked what I might be prepared to pay, and we ended up haggling. Since then, I've had a rule:
and I have been very glad of it on many occasions. I can go for a short walk to decide, and if I don't want it, I simply don't return to the shop. This means I'm deciding in calm surroundings, based on what I want rather than on embarrassment.
Are there other maxims I could adopt that would serve me equally well?
(Personal note: I'm in the Bay Area for a week after minicamp, Sunday July 29th to Sunday August 5th. Let's hang out, go to things together, help make my visit cooler! Mail me: paul at ciphergoth.org. Thanks!)