> This curbing of the positive (emotional attachment to friends and family) to make the negative less bad and more tolerable.
I don't know enough about stoicism to defend it fully here, but it is similar to Buddhism in it's prescription of asceticism and tempering of emotions. So taking the Buddhist angle to 'attachments', the idea is not that you do not enjoy the pleasure of others, but you don't burden yourself with the attachment itself. That is, spend time with your loved ones and enjoy their company, but if they leave you tomorrow, avail yourself of your attachment to their presence, so that you can better live in their absence.
I think with stoicism, also, it's not about living a joyless existence, in order to dampen the painful moments, but to steel yourself to the reality that all things are impermanent. Keep in mind that many stoics, including Epictetus, Aurelius, and later, Seneca, lived in a bloody times. In particular, Nero ordered Seneca to kill himself, and by most accounts, he did so dispassionately. It's perhaps the character of these times that suicide is thought about differently between stoicism and Buddhism.