It is what it is - Probably the dumbest one ever. You aren't actually saying anything when you say this. I never said it and then heard it too much and caught myself saying it. Ugh. Trying very hard to never say it.
If you have any questions - If you tell someone this, you aren't very bright. This implies you have all the answers. I already know you don't if you're saying this. Plus I'm obviously going to ask you if I have a question about something you said. I'm not going to ask my dog.
Anything with Professional in it - Just because you get paid to do something, doesn't mean you're good at it. Just because you don't get paid to do something, doesn't mean you're bad at it.
Expert - If you call yourself an expert, it's almost guaranteed you aren't.