I waited this moment for a long time, today I m going on holliday with my best friends, Laurent, Cédric and James. They are well-educated and we can have always a lot of fun with them but we can't say they're perfect, I mean the perfect friends doesn't exist, even if they have a lot of good personality traits, they have also a bad traits like Laurent he is intelligent and honest but somestimes he cab be arrogant or rude

Somestimes Sometimes.

Franchement la flemme de le faire. C'est un DM?

pas mal de petites fautes :/
2 ou 3: j'aurais plutot dit well-manerred que well-educated
pour intelligent, plutot smart, clever, ou brilliant, mais intelligent a une petite connotation "intello" je crois
Pour les autres fautes elles sont plus banales et tu peux les corriger tout seul je pense (orthographe ou bien grammaire).

je mettrais "always" avant "have" mais pas sûr

"I've been waiting for this moment"
"holiday"
"we always may have a lot of fun"
"the perfect friends don't exist" (3eme pers du plur)
"they also have bad traits"
"he may be arrogant"

Sinon mets plus de points que de virgules niveau ponctuation, ça sera moins lourd.