Happiness is a choice. You can decide in any situation whether to be happy about it or not.

My job frustrates the crap out of me, but I have one. = happy
Somebody else raised my son, but I have contact with him now, and a good relationship. = happy

Those are just two examples, but hopefully you get the idea. You can whine about how bad it is, or look for and focus on the good points instead. There isn't anything in life that is all good or all bad.