1. Don't say Jesus died when he was 33 years old.
The common assertion seems reasonable that if Jesus "began his ministry" when he "was about thirty years of age" (Luke 3:23) and engaged in a three-year ministry (John mentions three Passovers, and there might have been a fourth one), then he was 33 years old at the time of his death. However, virtually no scholar believes Jesus was actually 33 when he died. Jesus was born before Herod the Great issued the decree to execute "all the male children in Bethlehem and in all that region who were two years old or under" (Matt. 2:16, ESV) and before Herod died in the spring of 4 B.C. If Jesus was born in the fall of 5 or 6 B.C., and if we remember that we don't count the "0" between B.C. and A.D., then Jesus would have been 37 or 38 years old when he died in the spring of A.D. 33 (as we believe is most likely). Even if Jesus died in the year A.D. 30 (the only serious alternative date), he would have been 34 or 35, not 33 years old. No major doctrine is affected by this common misconception. But don't damage your credibility by confidently proclaiming "facts" from the pulpit that are not true.
2. Don't explain the apparent absence of a lamb at the Last Supper by only saying Jesus is the ultimate Passover Lamb.
While it is gloriously true that Jesus is "the Lamb of God, who takes away the sin of the world" (John 1:29), this does not mean there was no physical paschal lamb at the Lord's Supper. In fact, there almost certainly was: "Then came the day of Unleavened Bread, on which the Passover lamb [pascha] had to be sacrificed. So Jesus sent Peter and John, saying, 'Go and prepare the Passover [pascha] for us, that we may eat it [i.e., the pascha]'" (Luke 22:7–8; cf. Mark 14:12). Even if it isn't specifically mentioned in the Gospel accounts, eating the paschal lamb was an important part of every Jewish Passover (Ex. 12:3). This is why the disciples ate the meal together as a group, at night, within the city gates, where it would have been eaten with red wine and consumed before the breaking of bread and singing of a hymn. While there's disagreement about the nature of the Last Supper, we think it's clear that Jesus celebrated Passover with the Twelve on the night before the crucifixion—with Jesus making it clear that he saw himself in the tradition of God's mighty deliverance of his people Israel from bondage in Egypt by the blood of a sacrificial lamb.
3. Don't say the same crowds worshiped Jesus on Palm Sunday and then cried out for his crucifixion on Good Friday.
This kind of statement makes for a powerful sermon point to illustrate the fickleness of the human heart when it comes to Jesus the Messiah. But a couple of qualifications need to be added. First, it is not entirely clear that the "Hosanna!" crowd acclaiming Jesus' triumphal entry is the same group of people as the "Crucify him!" crowd gathered before Pontius Pilate. The former seem to be mainly pilgrims from Galilee along with Jesus's disciples, while the latter seem to be largely those from Jerusalem. Second, both crowds are expressing passion based on misunderstanding. As Jesus rode into Jerusalem on a donkey, the excitement of those proclaiming "Hosanna!" was based on an erroneous nationalistic conception of the Messiah. And when Jesus stood with Pontius Pilate before the Jerusalem Jews, stirred up by their leaders who were falsely charging Jesus with blasphemy, their condemnation was likewise based on a misconception of the Messiah's identity. The common bond between both crowds is not the fickleness of the human heart but the lack of genuine knowledge and worship of the humble Messiah and suffering Servant.