Some bad things to say at work and in general:

There are some words and phrases people frequently utter, without realizing they’re making themselves sound noncommittal, undependable or untrustworthy. It's a really good idea to limit use of these words and find alternatives. Forbes wrote a more in depth article about the relevance of this pertaining to work, however I believe their points are well taken for all situations.

1. “Try” – Even if you don’t mean it, when you say you’ll try to do something, others will think you’re just paying lip service and have no intention of getting it done.
2. “I’ll get back to you” – People often use this phrase to buy some time, and never actually get back to the person they say it to. To avoid giving that impression, specify the day and time when you’ll touch base.
3. “We’ll see” – This is most often used as a way to avoid confrontation or having to say “no.” Instead, just be honest.
4. “I guess … ” – It’s a common phrase people often tack on to the beginning of their thoughts. But it can also give off the impression you aren’t really sure of what you’re talking about.
5. “If” – People use this as a way to shift blame — for example, by saying something like, “If Bob finishes his part, then I can do my part.” It’s better to avoid the “if” and assume a successful outcome.

I believe all of these statements are vague and don't do the communicator justice.