Neither of these two behaviors will hold out against the judgment of Almighty God. In yesterday's gospel reading for Mass, Jesus gives us the parable of the King who invited people to a wedding feast for his son. Those who were invited refuse to come for one reason or another, but they are all doing one of these two behaviors listed above. Either they are making excuses not to come, or they respond with an attitude of superiority (even to killing the servants who invite them!).
The symbol that Jesus is displaying for us in this parable is His own invitation to us to come into His Kingdom and enjoy the fruits of it. We could describe it this way: Jesus says "I have a great blessing for you, but you have to do the work of getting here to receive it" and those invited say, "I don't need what you're offering". What do you do to justify your spiritual weaknesses (for we all have some)? Do you tell yourself that are already doing fine and do not need to do anything "extra"? Do you make excuses like "it's not required"? You may call it a "reason", but that does not make it right.
The attitude of spiritual superiority is something of a plague that the devil wants to infect us with. If we think that we are "too good" to need to work on our spirituality, then we will not only stagnate in our faith, but we will eventually fall into total apostasy. It was St. Jerome who said:
Be on your guard when you begin to mortify your body by abstinence and fasting, lest you imagine yourself to be perfect and a saint; for perfection does not consist in this virtue. It is only a help; a disposition; a means though a fitting one, for the attainment of true perfection.Good words that we should all take to heart, for each of us can be tempted to think too highly of the meagre actions that we perform in our spiritual disciplines.
Alternatively, the other attitude that says, "I know the blessings of Christ's Kingdom are good, but I should be excused from having to do the work because my situation is special", is a horrible cycle that the devil wants us to fall into. Make an excuse one time, and it is easier to make an even more lame excuse next time, ad nauseam. One translation of the gospel reading says that those invited "made light of the invitation". In other words, they went so far as to say "the wedding feast is nice, but it is not all that great". This means that they thought they were fine without it; but who will actually be fine without the grace of God on judgment day?
What is your normal weakness? "I'm doing great so I don't need more spiritual effort" or "I know I need it, but I have an excuse to skip out"? Whichever it is, then you need to begin working to overcome it. If you think you are doing fine, then sincerely ask God to let you see your spirituality as He does (remember the passage "be perfect as your Heavenly Father is perfect"?). If you are making excuses, then make a determination either to reject all excuses, or (if you really think you have one that is valid) then ask your priest about it--he is there to counsel you on this very type of issue. In this age of spiritual compromise, let us not get caught in the knot of self-justifying pride. The path of humility is the path to Heaven.