What a loaded question!
Happiness is based on perspective. We can be perfectly content with our cars (or our lives) until someone tells us that another car (or life) is better. But, really, nothing has changed with the car (or life) that we were happy with just a few minutes before.
If a happy villager from the 1400s were to visit your kitchen, would he be amazed at the food and resources you have in your pantry? Would he be shocked by how long we live, how many material possessions we own, and how much information we have at our finger tips? And, when he was transported back to his village and his era, would he feel the perceived loss and be less happy?
What do you have in your life, right now, that would make you happy if you didn’t know a “better” option existed? And what makes that other option “better”? Is someone trying to sell you a new model? Is someone trying to make themselves feel more successful or happy by making you feel less so? Is the constant yearning for the next thing or place or experience making you unhappy?
Then stop. Don’t play the game*. Be happy where you are and with what you have. The advertisements and social competition are yelling so loudly in your ears, but you don’t have to listen.
*I’m talking about general happiness, here, not depression. Depression is real and not something you can just decide to get over. If you’re depressed, you’re not alone and it’s okay. More okay and more normal than you probably realize. Take the time to invest in yourself by talking to a professional counsellor or therapist.