Disadvantage to calculate mean-
Advantage of mean

It is easy to calculate and understand.

Disadvantage of mean

Sometimes it may be unduly influenced by abnormal values (either very high or very low) in the distribution.

For example, the income of seven people per day in rupees was as follows -
5, 5, 5, 7,10, 20, 300 = 352
Mean = 352/7 = 50.3

It has seriously affected mean because the income of 6 people is very low than the calculated mean and income of one is very high than calculated mean.
So, mean is not useful when the distribution of value is skewed (deviated) with some small number of very high values.
Difficult to calculate
Difficult to understand
May be influenced by abnormal high or low values
None