"We were traveling."
Jesus Christ is to be our priority above and beyond every other thing that can or will come into our lives (Matthew 6:33), and the worship of Him is the primary goal in Christianity (Ecclesiastes 12:13, John 4:24). Sure, there are other purposes to Christianity, like evangelism and benevolence (Matthew 28:19-20, James 1:27) but without the worship of Jesus those are nothing more than invitations to a social club and community activism! But, when a family fails to schedule where they will worship the Lord during their various travels they have not only failed Jesus, they have failed the brethren (cf. Hebrews 10:24-25) and, possibly more importantly, they have failed their children in that they have failed to teach the younger generations that a worshipful mindset is crucial to a good life (Ephesians 6:4-5).
I know that worship is sometimes on the back of the person's mind when he is driving the family van across the countryside and combating the "Are we there yet" questions and the relentless bathroom stops, but that isn't when we should schedule where we're going to worship! The decision should be made long before the family ever puts a bag in the car! It's more important than planning where the family will sleep while on vacation! In fact, it might make all the other decisions more easily answered when there is a amusement park down the street from the church building or a hotel on the same block.
No, this excuse is dangerous to the spiritual welfare of the one making the statement, the trip itinerary and the little ones that will one day grow up to take their families on similar trips only to "forget" to find a good church near their destination. Let's not let this excuse be our answer when we come home from an amazing trip because it's not a good trip if the family didn't take the time to do the most important thing they could have done while gone.
"We were just running behind and couldn't get there on time."
Let me say this, we all understand that families run late sometimes! And we all understand that some brethren can be a little too judgmental about it happening. But, which is more important, worshiping God in spirit and in truth regardless of the fact that you missed the first few songs and the announcements or completely failing to do so because you were worried about what people might say? We wouldn't allow people to think that we can fail to follow God because we are scared of people's opinion of us afterward with regard to any other command, why does attendance at worship change that? My understanding is, it doesn't.
Now, let me speak to those of us sitting in the church building when these families arrive somewhat disheveled because their family of 5 got ready to leave their house quicker than it takes to read this article. Paul made it very clear that we are to wait for one another when we're about to take the Lord's Supper and people are not present for one reason or another. But we know that this can't be a constant thing when it's a question if the person is even going to show up and the church would be left to take Communion at 11:00 pm each week to make sure everyone is there beforehand. No, the point of Paul's exhortation was that brethren should not judge one other with regard to "tardiness" and should understand and stop judging those that show up a little late. That doesn't take away the responsibility to prioritize and try to be on time, but there shouldn't be judging coming from brethren when a family is late!
"We're normally there, we just didn't really feel like it this week."
When you least feel like being at worship services, that's when you need to be there the most! That is when the devil is going to try his hardest to break you and if you are absent you aren't doing anything to to help yourself fight him. I believe this is why the Lord commanded that His Christians meet weekly (cf. Acts 20:7, 1 Corinthians 16:2). He knows what is best, that is the guiding factor in His giving laws and ordinances to follow, and He knew that we need regular fellowship and worship together to stay strong and stand against Satan and temptation. And if we aren't there for that encouragement (cf. Hebrews 10:24) we have opened ourselves up for an attack that we will not be able to fight alone.