Not once I wished I had some skills at that time to deal with complaining differently but nevertheless it was a great lesson and in some odd way probably instigated my professional journey (NLP & positive psychology).
Have you ever lived complain-free life?
Just as an experiment, try the following exercises and monitor how it impacts the quality of your life.
Refrain from complaining for 24hrs. Simply allow thoughts to come and go and if you catch yourself complaining simply start another 24hrs non-complaining shift.
For the next week do not gossip or accept others gossiping. If you catch yourself wanting to gossip just break the state, confuse yourself and say something else. If others start gossiping - ask them to stop since you are on the one week gossip-fasting or do anything else that may help you help them not gossip. If none of these work then just start from the beginning for the week of no gossiping.
For the next month don't criticize anybody who are your friends and family. Same rules apply.
For the next hour don't criticize yourself.
exercises by Michael Neill, www.geniuscatalyst.com