A very challenging way to help improve your mentality of these angry thoughts would be to stand up to yourself.  Being brave enough to tell yourself you are wrong is harder than telling someone else they are wrong in my eyes.  I think it's scary to not agree with yourself but sometimes we let our thoughts get so out of hand that we don't trust anyone.  We always think that the next person that I meet is going to either hurt me, cheat me, steal from me or lie to me.  Somewhere along the line we have all become so guarded that we don't even trust ourselves.  For example, me being a woman I can associate with doing this, our loved one tells us they will call us back as soon as they finish whatever it is they are doing.  Well, two hours later, knowing that they are done with whatever it is they were doing, we are hotter than a jalepeno in the desert that they have not called us back yet.  "He is cheating on me, he is ignoring me, why does he not love me enough to just call?"  Yes we all do this!  We are insecure!  We cannot take it out on our loved ones because we have a trust problem.  Especially if you know they are forgettful, extremely busy and overworked!  It's so easy to do that.  For pete's sake, I do it so much, I find myself apologizing to people for it more than I actually use my phone.  It is not intentional but we have this internal nature to doubt people.  Well, "stop it!"  I have lost a lot of loves ones because of my innability to see things for what they really are.  We can't expect people to drop everything for us all of the time and vice versa.  I really stand by the quote, "do onto others as you want done to you".  I probably said that wrong but you get my point.  You need to tell yourself to quit being selfish and spoiled when you catch yourself doing this to people. 

When I get sad about something, I ask myself if i am really upset or am I just mad that I didn't get my way.  If I have thoughts of loved ones not really loving me, or of my significant other lying to me, I have to tell myself to stop.  If I don't I can expect myself to start crying and being depressive.  When I basically yell at myself, I quickly remember they really do love me and he is not lying to me.  We all have bad days, that can make us irritable and just down right mentally exhausted to the point that we say things we don't mean. 

I tell you what though, when you can learn to do these things, it feels so good to hear that person say, thank you for understanding how I was feeling.  That person then knows even more how much you care for and love them and that they can always expect you to be there for them.  That right there will help deepen your appreciation for someone and keep them close in your life.