We've all dated someone with 'issues' - whether their emotional baggage stems from childhood experiences, or previous relationships or life trauma, it's never fun to be saddled with their drama or responses colored by their bitterness. Some of the common ones and warning signs are included here.
Some people come from dysfunctional backgrounds and upbringing, and will carry this with them. It can show itself as a warning for you, in the form of frequent defensiveness, victim-hood (emotional martyrdom), manipulation/ emotional blackmail, or active abuse. If there are too many angry outbursts or continual blaming, it might be time to either address that issue or move on.
Depression and moodiness can also color a relationship in a negative way. Whatever the reason, as understanding as one tries to be, it is really going to take its toll eventually. While there is no blame on someone battling depression, it can be very draining and unfair on their partner. Clearly this is a difficult situation for both parties; a depressed person doesn't WANT to be depressed - which only makes things worse. But their irritation and moods can cause distance between a couple. You have to ask yourself if this is something you can potentially deal with for the rest of your life... As depression can sometimes come and go.
The ex... If there are too many mentions of the ex-lover, photos or keepsakes and hints at how great/ different they were, cryptic social media statuses, mentions of the ex among friends.. You might find yourself dating a rebounder. When you are someone's rebound, you can find yourself left empty and alone after they have healed and moved on (or gone back to their ex...) Taking your energy and support and time, then scarpering back to their "real life". Be very careful about the ex-factor, as it were!
It's not fair on the next partner to bring baggage from the past into the relationship. Those suffering from this can see a therapist and make peace with who you are and where you are, before trying to connect with someone else. Or spend some time with friends or escort companions, sharing your feelings and gaining the support you need, until you feel strong and ready for a mature, healthy relationship again.