The prospect of war in the Middle East is frightening, and the downturn in the economy is depressing, but it's more likely the small things in life that play a determining influence on your mood on any particular day.
You know the sort of thing I mean: the length of the queue in the bank, the car stalled on the yellow box that blocks your path, the offhand response of a waitress, the hammer that misses the nail and hits your thumb.
Many things we are helpless to control - take the weather, the cycles of the economy or the mind of George W. Bush. But others can be grouped together - for my purpose today - under the title of "it doesn't have to be that way".
The statistics tell us that we live in the fourth wealthiest State in the world these days - yet we have a creaking infrastructure, substandard social services and underdeveloped attitudes to the environment and outsiders.
But even allowing for the game of catch-up we are currently playing, life in Ireland is full of unnecessary travails. Lack of money, the cutting of corners, laziness and incompetence are sometimes the culprits, but so many daily irritants can be blamed on bad design.
The devil is in the detail, and every day throws up new examples. My current favourites are the glass and chrome taxi shelters that have sprung up recently around Dublin city's centre. They look nice, they mean well - and hardly anyone uses them.
Take the shelter outside Heuston Station, which I pass most mornings.
Even on wet mornings, no-one uses the shelter. Hundreds of would-be taxi passengers disembark from the provincial trains and form an orderly queue outside.
The queue starts beyond the shelter, snakes around the back and continues down to the entrance to the station. Everyone is exposed to the elements, but no-one wants to risk using the shelter for fear of losing his or her place in the queue.
That's because the shelters weren't designed with a Dublin taxi queue in mind. People go to taxi-stands only because they can't hail them on the street. By their nature, such queues are long; if they were short, they would dissolve quickly as the taxis come.
Even when there are plenty of taxis available, passengers have to queue for far longer than should be necessary, because the process of matching customers with cars is so cumbersome.
At least in this case, the designers meant well. Just what the creators of the car-park in Tallaght Hospital were thinking I don't know. Anyone who has visited a patient here will know this building is something of an obstacle course, where the aim is to get your car out safely without bashing it into any of the walls that seem to loom so threateningly from all directions.
A particular challenge is presented by the journey to the upper floors, via a series of perilously narrow passageways. Black marks on the walls and torn away bollards tell the tale of the many cars that failed to negotiate the turning space without scraping their bodywork against the surrounding walls.
Bonus points are available for anyone who can steer a path at the exit of the car-park to the right-hand ticket machine without hitting the kerb - I've yet to manage it.
Tight parking lots are commonplace in many modern apartment blocks; they can be explained but not excused by the fact that land is so expensive in urban centres. But Tallaght Hospital doesn't have this excuse; it was built on a green-field site, with plenty of green space around.
Taps are another bugbear of mine. Mixer taps that deliver the desired combination of hot and cold water down a long spout have been commonplace in other European countries for years, and are fairly common now in many Irish homes. Yet how many public places force us to use spring-loaded and separate hot and cold taps? You know the sort I'm talking about; you press them with the palm of your hand, but the flow of water stops before your fingers are under the tap.
You'd fill the basin with water but the plug is missing. So you wash your hands awkwardly one at a time, while using the other hand to keep the water flowing - headbutting the tap is another method but not recommended.
Even Croke Park's much-praised redevelopment has had its problems. On more than a few Sundays last year, spectators at the front of the New Stand got a severe drenching because the roof didn't extend far enough forward.
"If you were to design a house in a similar fashion where the wind blew into your sitting-room while you watched Coronation Street you would nearly be certified," GAA manager Mick O'Dwyer was led to comment. The stand's architects have promised the situation is better now that the Hogan Stand opposite has been redeveloped.
I could go on - why, for example, does it take so long to board passengers on a bus or a plane? - but readers might like to send their own favourites to me at this email address: