Every time we say or think self damaging or deprecating remarks, it's like making a little cut or tear in ourselves. The more you do it, the deeper and more severe the cut becomes until the substructure finally gives way.
A friend of mine who is an engineer was explaining to me what happened a week or so ago at the Chevron refinery in Richmond where there was a fire. The pipe that burst was not... one of the ones that was replaced regularly. Those that are known to crack or break - say at 5 years of service - are on a replacement schedule every 3.5 years so a break can be avoided. The one that broke wasn't one of these. It was a pipe that had been in service for probably 35 years carrying heated clean diesel. And while there were no visible signs of pitting or damage, over that period of time, the high temperatures gradually caused infinitesimal breaks. So over the course of years, these little breaks went undetected, and no instruments picked up the wear or the loss of structure. Ultimately, the pipe lost the ability to hold together, rupturing and causing the fire.
We do the same damage to ourselves each time we talk down about us - what we can't do, how we aren't smart enough or good enough or whatever enough. And over time, the damage is done and we believe and become what we are saying - even if it wasn't true.
Take a moment each day and remind yourself of all the things you did well, of all the positives in your person, your life, your environment. Doing this reinforces and builds your sense of self. Try it, you might like it and you better. Have a great day, you awesome human being!.