Alcohol is good

New Guy, Friend-Visiting-From-Out-Of-Town and I went out for drinks on Saturday night. We started off at 17h30 at a happy hour and left the fourth pub at 1h15 this Sunday morning. Here's what NG volunteered:

1. Bossman has told him that I am a very good teacher a few times.

2. A big reason that other colleagues have a negative attitude towards me because when I say, 'No,' they think I'm telling them to fuck off.
Example:
Random Colleague: 'Mr T, do you know of any good games or activities for (insert grammar point)?'
MrT: 'No, sorry I don't.'

Apparently that means 'fuck off' to many of my colleagues. When I say 'No', I mean 'No', not 'Fuck off'. If I wanted to tell someone to 'Fuck off', I'd say 'Fuck off'.