Over 43 years.....
... I've been given tons of advice, and some of it I have actually listened to. Here are a few faves:

John:
Personal experimentation will prove that the shortest distance between two pubs is rarely a straight line.

Dad:
I don't ever want to have to bail you out of jail for anything criminal. If you get arrested standing up for what you believe in, that's ok - anything else will break your mother's heart.

Cousin Nik:
No-one ever drowned in a shallow relationship.

Mr Harris:
Never go out with a woman that is a hooker, a drug addict, or works in sales, or HR. Because they will never ever give you a straight and truthful answer.

And a couple of my own:
Money doesn't buy you happiness, but it can get you a better class of misery.

A wise person learns from their mistakes; a wiser person learns from the mistakes of others.

If your woman asks you if - hypothetically - you would like to shag any of her sisters or friends, ALWAYS answer 'no'.
If you wish to keep your bollocks in the vicinity of your body, trust me - there is no other answer!
(Sebulba continues to fight evil with evil....., Sat 22 May 2010, 12:08, 3 replies)

In regards to the last one
What if she is your sister? ALso the whole 'My mate fancies your mate' senario?
( riverghost servicing your mum since, Sat 22 May 2010, 12:16, closed)

What?
are you still in primary school? That's that last time anyone I know used he "my friend likes you/your friend" bullshit.
(M61A1 CUPID- STUNTS, Sat 22 May 2010, 12:39, closed)

As for the last one
How do you know that she's not trying to set up a threesome for your birthday present? You could be seriously missing out there.
(mmm....beer, Sat 22 May 2010, 18:00, closed)