I am making a list of common PHP mistakes and I need your opinion!!!!

[regindk]

Ok, I've made a list of common PHP mistakes I got then points so far... Praticly these are based on my own subjective opinion. However I'd like to hear your inputs... I won't post the full list untill I got some input (I don't want to influence your input too much)!

Well the two first (I think) are pretty clear:
1:  Not escaping entities.
2:  Not escaping sql input.

Now let me hear your opinions!!! :D

[Kairu]

Personally I believe the most common for new users is forgetting either a semi-colon, or one of these { } (Can't remember what they are called o.0)

[ki]

nah its the echo thing


kids get the feeling they can do:

[code]echo "hi these are "quotation marks" see?";[/code]

when it should be

[code]echo "hi these are \"quotation marks\" see?";[/code]
and also people ending the code with ;