When gioven two choices, pick the one that makes partner happy.
An auction last night illustrates this. My partner, a good club player, opened a 19-count 4-1-4-4 hand 1C. Whether you approve or would bid 1D is not relevant to the story, so assume 1C is OK.
I now bid 1D. Partner had two plausible options. The one he chose was 2S, a game-forcing jump shift. Whether my call was right or wrong, I had somewhat of a problem deciding what to do. In an undiscussed partnership, I decided to be practical, because my hand was not that fascinating. My stiff club certainly looked bad. So, with a marginal decision, I opted to bid 3NT to slow the auction down, hoping for at least a useful stiff honor to increase the chances that the suit was stopped. In practice, the cards were just so, and the opponents could take the first five five heart tricks. Partner also opted to pass for the same "practical" reasons.
What if, however, partner has instead opted the "happy" bid of 3H, a splinter?
Now, I ignore the stupid "practical" option because my 5-card diamond suit and stiff club suggests slam. In fact, 6D is laydown.
The point is that, among reasonable options, pick the one that makes partner smile if you want him to smile. Bidding 2S, in the example, might have achieved a 2NT or 3C or 3D call by me, and then partner might have made a very descriptive 3D call. His great spade suit would then be underlined, and the shortness in hearts would be inferred rather than shown. But, the plan did not work when I, as partner, made a judgment call based on the info to date and when the plan seemed suddenly bad as to entry into the four-level.