|One way to increase happiness is to lower your expectations.|
If I expect the trains to run on time I'll be sad because they rarely do. But if I expect them to be late and I bring something to do, then it's not as bad.
If I expect to get a large bonus and I don't get one, I'm sad! But if I don't expect a bonus and get one, I'm happy.
If there's a bug in my software I'm sad. But if I expected there to be bugs and there is, I'm not that sad or angry.
If someone leaves the toilet a mess at work or doesn't make coffee I can get angry. But if I expect people to behave this way it's not that bad.
So try lowering your expectations to see if happiness can be yours.