Again, what better place to pray for yourself and those distracting you! The benefits of even daily Mass (being in His presence) surely trump the inconvenience and distractions. If Mary was able to find peace at His feet, in the midst of Martha’s frenetic hustle and bustle, then I’m sure we can all do so at Mass whatever distractions may be on offer.
Remember His peace is not as the world gives, so it’s not necessarily a warm fuzzy feeling or anything.
To make it really simple - an invalid Mass, or any other invalid sacrament, is dangerous - not a sacrament at all, in fact. An illicit Mass, or any other illicitly celebrated sacrament, is still a sacrament, still effective, but it hasn’t been celebrated as it should have been.
Only three things make a Mass invalid. The first is wrong form - if the priest says the words of consecration ('This is my body … ’ ‘This is my blood…’) incorrectly or omits them.
The second is wrong matter (in this case the bread and wine, which must be pure wheat flour with no additives and the wine must be pure grape juice). So if there’s bits of fruit in the bread, or it tastes beyond doubt of honey or vanilla, or it’s unfermented grape juice instead of wine, you know that invalid matter has been used and it’s thus an invalid Mass.
The third is wrong** intention** - ie the priest does not intend to consecrate. This we cannot know unless the priest flat out says that he does not intend to consecrate (which is unlikely in the extreme). We can trust, all other things being equal, that correct (valid) intent exists.