'badness'? if you mean negative energy try a cleansing and protection. if you mean a negative person try a banishing. if you mean negative thoughts and emotions try a counselor and meditation.
it's wise to do a regular cleansing and protection [as well as daily shielding] since we brush against negative energy all day [could be from negative situations or a really bad day] and this energy sticks to us, just as we wash away physical dirt, you should regularly wash away the spiritual dirt.
if you discover a person in your life that always brings you down and makes you feel bad, magickally you could banish them so they don't feel comfortable around you and/or stop wanting you be around you. of course i would assess the situation, if it's a family member or a friend going though a tough time that's dragging you down, reflect on the situation as a whole and ask yourself if it's worth fighting for. i've had people in my life who were poison [friends and family] some i fought for, others i cut out, but in the end, these people left my life. they didn't want to change their poisonous ways and it left me in a dark place. people whom refuse to change [could like who they are despite being destructive, or refuse to deal with substance abuse and/or their demons] you should seriously consider your options, is this person worth drinking poison for, or is your well being more important [only you can answer that question] in these situations a banishing to keep them away.
if you have depression, or notice you are becoming someone you don't wish to be [bitter, hateful, judgmental, negative] i don't believe there is a spell for that, only personal development. sometimes you can catch a cycle early and through meditation, mindfulness, journaling, and reflection, you can break the cycle and create a new habit. other times [say in the case of mental health issues like depression, anger management, and trauma] you might wish to also speak with a qualified professional. you might simply need someone to talk to, or perhaps you need medication and regular sessions. the key is to take the step to help yourself. good luck to you.
I pretty much 100% agree with Nekoshema on this but wanted to add that in the case of depression there are some shortcuts to feeling better that can really help, no-one likes to hear it but diet, exercise and hydration REALLY help. Gyms are boring and running isn't for everyone but think about interesting stuff like kayaking or rock climbing (clubs can lend you equipment and membership is much cheaper than buying stuff yourself- they'll also teach you). At the very very least, stay hydrated. Your body physically cannot produce happy hormones if you are dehydrated and it is genuinely the easiest way to kickstart an upward spiral :)
Grace has a point, when you're depressed you'll tell yourself a handful of peanuts is a fine meal and crawl back into bed. sunlight, fresh air, good food, moving your body, these can help. [even if you're not depressed, even if you're having a good day, it can help in many ways] it can be hard to break the cycle [i know] but some days you need to push yourself to spend a hour in the fresh air [other days you need to watching Disney movies over and over and cry] you really shouldn't self diagnose your depression since there's many types and treatments, but food can effect mood [sorry for the rhyme]