Hm, thinking about bad habits of mine, the first came to my mind was leaving the PC turned on always unless I am asleep or away for a long time.
Even I watched a cricket match or a movie on TV I tend to leave the PC turned on thinking I must check my email account etc time to time. Even I could do that on my phone, I can’t make my mind to turn the PC off.
This habit is reducing my PC’s and router’s life time and consuming electricity. But, nothing to do, I have to leave the PC turned on, just in case I might suddenly need it.