My daughter has been vegan for the last 8 years and in that time we have all had a taste of a vegan diet, January vegan and so on. Some of the foods ard delicious but I could not live as a vegan, I'm OK for a day or two.
My daughter takes supplements but the question remains about the lack of
essential fatty acids which are only animal based. There is an Australian doctor that says for this reason, 2 essential fatty acids missing from a vegan diet, the diet is not advisable.
It's my observation that vegans get a bad reputation because some of them take it as a religion; thankfully my daughter is not like that and she says the diet helps her control the allergies she used to suffer from, however, she has a friend that everytime she comes to the house for a visit, she finds a way the bring the subject up and she does it in such a way that I just walk out or leave the table, etc.
EDIT
To add a bit of extra info:
Essential fatty acid
Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. The term "essential fatty acid" refers to fatty acids required for biological processes but does not include the fats that only act as fuel. Essential fatty acids should not be confused with essential oils, which are "essential" in the sense of being a concentrated essence. Only two fatty acids are known to be essential for humans: alpha-linolenic acid and linoleic acid. Some other fatty acids are sometimes classified as "conditionally essential", meaning that they can become essential under some developmental or disease conditions; examples include docosahexaenoic acid and gamma-linolenic acid. When the two EFAs were discovered in 1923, they were designated "vitamin F", but in 1929, research on rats showed that the two EFAs are better classified as fats rather than vitamins.
Wikipedia