There is (specific) meaning in suffering

Suffering is like a gas - it fills whatever available space

Sadness points us in a direction - that’s the meaning in it - too much sadness can break us so it’s important to manage the levels. Like a push that’s too hard, we fall instead of being propelled forward.

Stuff with [person] reminds us of what is truly important: family, health, togetherness, support. Even when it’s hard

Danger of sadness is numbness - too much or too extreme trauma and we’ll react by desensitizing ourselves and emotionally blunt ourselves - danger is that we lose feeling in that part of our lives and cut out the good feelings too. Sadness exists alongside happiness so if one goes they both go. Depression can be a reaction of sadness at the loss of happiness towards something else in our lives, ie we get sad that we don’t get happy anymore about something, which is a valid sadness.

If the emotional blunting is too general or pertains to something very prominent in our lives then it can become depression.

Sadness points us in a direction. Depression occurs when we don’t move in that direction, possibly because it’s too far & we lose hope that we can get there. With depression is hopelessness which gets us stuck in that sadness. Over time that can lead to emotional numbness which can make it even harder to get out of depression because we no longer have the sadness giving us a nudge.

Meaning in this specific instance: this is a small price to pay for having such a wonderful [person] in my life. Another instance: I asked God/whatever powers may be for something that might help me mature.