Are our email filters too efficient?

This morning I discovered that a local person who had been trying to email me needed to try 3 times before one got through. Normally this could not have happened because my ISP is not in the habit of blocking normal web traffic.

Unfortunately, many internet service providers have had to upgrade security on regular email accounts to prevent unsolicited junk messages which have annoyed most of us for a long time.

Could it be that some of the innocent words in those emails (properly used) could have been seen by the filters as being commercial junk mail?

The fact is that from time to time most of us either communicate with businesses or order items from them on line.

Are we to take this as an inevitable consequence of that legacy, or start looking for a new bug in the system?