The ability to forget unimportant stuff may be important to remembering the important things in the long term. So I would never use such a drug unless it had been tested for decades and shown not to have negative long-term effects on memory.
Another possibility is that a drug comes along and enhances cognitive function with minimal side effects, and while the long term effects are virtually unknown, users of these drugs outcompete those who don't. What do you think any appropriate response to such a situation might be?
