What are some ways to enjoy life with children more?
I am assuming you are talking about a situation where you are living together with children, typically family members. There is no universally correct answer to this question as enjoyment is deeply subjective but there are similarities across families from many cultures and time periods. For example, a common reason why children can make life less enjoyable for their parents is that they require a lot of care and attention which can be very stressful for the parents, especially if they also need to work or if their sleep cycle gets disrupted. Unfortunately there is no easy way to reduce this workload but you may be able to get help from others. Is your partner putting in enough effort? Maybe you have close friends or family members that can help you out.

Another common occurrence with children that can be stressful is if they are being uncooperative. For example, a child may refuse to eat their food. Again, there is no universal solution for this because the ways that a child can be persuaded will vary depending on their personality. Maybe they feel jealous of their younger sibling so something like Well, if you don't want to eat it I'll give it to your little brother may work to persuade a two or three year old child. You will need to understand the psychology of your child to find solutions that work for you. To get ideas you can try asking other parents.

Try to find activities that you can do with your children or siblings that both of you enjoy. Maybe you both like sports or watching certain types of movies. Maybe your child is interested in something that you care deeply about so you can get a sense of fulfillment by teaching them about it. Maybe you like playing video games so you can give one of the controllers to your child (if they're young enough they won't notice that it's turned off). Just make sure to remember that children can be very impulsive. They may for example say that they want a pet but then once they have the pet quickly lose interest or not want to do the work required to take care of the pet. So try to invest not too much effort in the beginning before you know whether the child is actually interested or you will be frustrated. Before you commit to something you can usually wait some time to see if the child stays interested in a thing or whether they were just acting on their impulses.

Finally, conventional methods for relaxation and feeling more happy with your life work with life situations with children as well. For example, every evening you can try to write down three things that went well that day. There is some research to suggest that this makes people happier and reduces stress because they are more aware of the good things in their lives. If you have the time you may also find it enjoyable to attend things like yoga classes to relax yourself; there are even specialized classes to attend with babies. Maybe a change in perspective is all you need.
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