You know those people who keep changing their story about a particular event when questions are asked?
They may convince you for a while but, sooner or later, you begin to think they are full of it, and doubts about their credibility enter your head.
You think less of those people. You think twice about whether or not they can be trusted.
Last week, the Government rammed through legislation to extend the emergency Covid powers until next February, on frankly legally dubious grounds.
Then, this week, we saw a significant moving of the goalposts by our twin governments — the actual Cabinet and the National Public Health Emergency Team (Nphet) — regarding the continued use of Covid restrictions in the months ahead.
On Tuesday, the Cabinet approved, on a partial basis, the next phase of the reopening of society. However, it came with a very large caveat.
Only three weeks ago, we were told that the use of Covid certs would be eliminated on Friday, but now they will be with us until at least next February.
The retention of the cert was seen as the only viable mechanism available to allow nightclubs and other live venues to reopen.
As with many other temporary measures — such as the universal social charge and, well, taxation in general — we are now well on the road to either semi- or full permanency with this thing.
Whatever about its use in nightclubs, the Government has not produced any evidence that would justify the extension or expansion of the system outside hospitality settings.
There is also a more sinister side to the continuation of the use of Covid certs.
There are many thousands of people, possibly as many as 700,000 — and far beyond the conspiracy theorist anti-vaxxers — who, for one reason or another, have not taken the vaccination jabs.
Many have been unable to do so for medical reasons, while others have genuine ethical dilemmas about the vaccine.
The discriminatory tone of the public discussion around this is somewhat galling.
The rather nasty vilification from on high of those not vaccinated has an authoritarian air to it.
They have basically been told take the jab and shut up. If you don’t take the jab, shut up and stay in your room. This is not acceptable in what should be a functioning democracy.
We may disagree with people but, as adults, they have choice. They should be accommodated in a far more meaningful way and not discriminated against in the manner proposed.
Friday's reopening of the late-night sector should have been a cause for genuine celebration, but it has been sullied by the shambolic handling of the guidelines issue by Catherine Martin, the arts minister, this week.
Scrambling to get guidelines out with just hours to spare was far from ideal, and continued ambiguity ill behoves lawmakers who should have had this prepared weeks ago, especially as the October 22 deadline had been set in stone since the summer.
Since last year, as Ireland grappled with lockdowns and restrictions, we were told vaccines would be our silver bullet once developed.
Once they were developed, we were told that we can only ease restrictions when we have a sufficient cohort of the population vaccinated.
Once we got to 80% vaccinated, we were told we would need to get to 90% vaccinated before life could return to normal.
“These vaccines are transformative and they are our way out,” Taoiseach Micheál Martin told us in March of this year amid sluggish supply at that stage from Europe.
This was echoed by Tánaiste Leo Varadkar, and virtually every Cabinet minister who appeared on the airwaves at that time.
However, this week, the decision to push out the deadline for the abolition of restrictions came against the backdrop of rising case numbers, notwithstanding the extraordinarily high vaccination rates throughout the State. These case numbers have led many, if not all of us, to ask what the hell is going on?
Why, when we were promised that vaccinations would deliver us to the promised land of freedom, is the narrative now changing?
From chief medical officer Tony Holohan and Nphet, to Trinity professor Luke O’Neill, plenty of people have sought to explain why our case numbers are so high but the explanations have been far from convincing.
Now we are told vaccines on their own are not enough.
We must continue with limiting people’s freedoms much longer than most other countries are doing, and for much longer than we were told we would have to do so.
I am no epidemiologist and I understand this virus is unpredictable. I get that it has ruined many a plan, not just here but across the world.
However, what is in question is the narrative presented to a patient Irish population. That narrative is no longer credible.
Another significant shift this week concerned the role of Nphet itself.
This unelected body, given huge public prominence and significance over the past 20 months, was set to fade into the background.
However, Dr Holohan told us that he and his band of not-so-merry folk are to remain hovering over us for the foreseeable future.
What’s worse is that, buried in his latest letter to the Government, is the threat that the country could very well have to return into lockdown should things not improve.
Ever-shifting goalposts and mixed messaging are never a recipe for success.
How can we, with more than 93% of people vaccinated, still be looking at having to go back into any form of enhanced restrictions?
How is it feasible that while we have fewer than 100 people in intensive care due to Covid or because they have Covid in conjunction with another illness, a population of more than 5m people is facing restrictions?
Were we lied to by our political leaders earlier this year as to the potential impact of the vaccine rollout?
God knows, it would not be the first time the public has been deceived by its political leaders.
Better answers are required of our leaders, who are seeking to impose restrictions on our free movement until the spring.
Charles Stewart Parnell famously said that no man has the right to fix the boundary to the march of a nation.
That is true, unless you are Nphet and the Government that has granted it too much power.