That's what I used to think.

[99bottles]

Context: A young and immature person and an old, mature person disagree about something. (E.g. The young person thinks that smoking isn't harmful.) The older person says...

That's/That was what I used to believe (too), but you're wrong.

Questions:
1. Should I put That's or That was?
2. Is too at the end of the sentence redundant and/or confusing?

 

[5jj]

1 - I'd use that's , but I think that was is also possible.
2. Why do you think it could be confusing?

 

[99bottles]

2. Why do you think it could be confusing?

2. Because with too it might sound as if the young person used to believe that in the past too.

 

[5jj]

It doesn't.

 

[emsr2d2]

Context: A young and immature person and an old, mature person disagree about something. (E.g. The young person thinks that smoking isn't harmful.) The older person says ...

That's/That was what I used to believe (too), but you're wrong.

Questions:
1. Should I put That's or That was?
2. Is too at the end of the sentence redundant and/or confusing?